diff --git a/libraries/ESP8266WiFi/examples/BearSSL_CertStore/certs-from-mozilla.py b/libraries/ESP8266WiFi/examples/BearSSL_CertStore/certs-from-mozilla.py
index 80dbc48387..edf3aa705d 100755
--- a/libraries/ESP8266WiFi/examples/BearSSL_CertStore/certs-from-mozilla.py
+++ b/libraries/ESP8266WiFi/examples/BearSSL_CertStore/certs-from-mozilla.py
@@ -13,15 +13,9 @@
 import sys
 from shutil import which
 
-from subprocess import Popen, PIPE, call
-try:
-    from urllib.request import urlopen
-except Exception:
-    from urllib2 import urlopen
-try:
-    from StringIO import StringIO
-except Exception:
-    from io import StringIO
+from io import StringIO
+from subprocess import Popen, PIPE, call, CalledProcessError
+from urllib.request import urlopen
 
 # check if ar and openssl are available
 if which('ar') is None and not os.path.isfile('./ar') and not os.path.isfile('./ar.exe'):
@@ -62,10 +56,10 @@
     thisPem = pems[i].replace("'", "")
     print(names[i] + " -> " + certName)
     ssl = Popen(['openssl','x509','-inform','PEM','-outform','DER','-out', certName], shell = False, stdin = PIPE)
-    pipe = ssl.stdin
-    pipe.write(thisPem.encode('utf-8'))
-    pipe.close()
-    ssl.wait()
+    ssl.communicate(thisPem.encode('utf-8'))
+    ret = ssl.wait()
+    if ret != 0:
+        raise CalledProcessError(ret, certName)
     if os.path.exists(certName):
         derFiles.append(certName)
         idx = idx + 1
diff --git a/tests/device/Makefile b/tests/device/Makefile
index cbbd34728a..f89c9ea93e 100644
--- a/tests/device/Makefile
+++ b/tests/device/Makefile
@@ -1,45 +1,65 @@
 SHELL := /bin/bash
-V ?= 0
-ESP8266_CORE_PATH ?= $(realpath ../..)
-BUILD_DIR ?= $(PWD)/.build
-HARDWARE_DIR ?= $(PWD)/.hardware
+
+ESP8266_CORE_PATH ?= $(shell git rev-parse --show-toplevel)
+
+BUILD_DIR ?= $(PWD)/build
+BS_DIR ?= $(PWD)/libraries/BSTest
+
 PYTHON ?= python3
 ESPTOOL ?= $(PYTHON) $(ESP8266_CORE_PATH)/tools/esptool/esptool.py
-MKSPIFFS ?= $(ESP8266_CORE_PATH)/tools/mkspiffs/mkspiffs
+
+VENV_PYTHON ?= $(BS_DIR)/virtualenv/bin/python
+VENV_JUNIT2HTML ?= $(BS_DIR)/virtualenv/bin/junit2html
+
+MKFS ?= $(ESP8266_CORE_PATH)/tools/mklittlefs/mklittlefs
+
 UPLOAD_PORT ?= $(shell ls /dev/tty* | grep -m 1 -i USB)
 UPLOAD_BAUD ?= 460800
-UPLOAD_BOARD ?= nodemcu
-BS_DIR ?= libraries/BSTest
-DEBUG_LEVEL ?= lvl=None____
-FQBN ?= esp8266com:esp8266:generic:xtal=160,FlashFreq=40,FlashMode=dio,baud=115200,eesz=4M1M,ip=lm2f,ResetMethod=nodemcu,dbg=Serial,$(DEBUG_LEVEL)
-BUILD_TOOL := $(ARDUINO_IDE_PATH)/arduino-builder
+
+TEST_BAUD ?= 115200
+BUILD_TOOL ?= arduino-cli
+
+BUILD_BOARD ?= generic
+BUILD_CPU ?= 160
+BUILD_SIZE ?= 4M1M
+BUILD_LWIP ?= lm2f
+BUILD_EXTRA ?= ,dbg=Serial,lvl=CORE
+
+FQBN ?= esp8266com:esp8266:$(BUILD_BOARD):xtal=$(BUILD_CPU),baud=$(TEST_BAUD),eesz=$(BUILD_SIZE),ip=$(BUILD_LWIP)$(BUILD_EXTRA)
+
 TEST_CONFIG := test_env.cfg
+TEST_RESULT_XML := test_result.xml
 TEST_REPORT_XML := test_report.xml
 TEST_REPORT_HTML := test_report.html
 
-ifeq ("$(MOCK)", "1")
-# To enable a test for mock testing, just rename dir+files to '*_sw_*'
-TEST_LIST ?= $(wildcard test_sw_*/*.ino)
-else
 TEST_LIST ?= $(wildcard test_*/*.ino)
+BUILD_FLAGS ?=
+BS_FLAGS ?=
+
+# To enable a test for mock testing, just rename dir+files to '*_sw_*'
+ifeq ("$(MOCK)", "1")
+	TEST_LIST := $(filter test_sw_%.ino,$(TEST_LIST))
+	NO_UPLOAD := 1
+	NO_RUN := 1
 endif
 
-ifneq ("$(V)","1")
-	SILENT = @
-	REDIR = >& /dev/null
-else
-	BUILDER_DEBUG_FLAG = -verbose
-	RUNNER_DEBUG_FLAG = -d
-	#UPLOAD_VERBOSE_FLAG = -v
+# To enable verbose mode, call `make V=1` ...
+V ?= 0
+ifeq ("$(V)", "1")
+	BUILD_FLAGS += --verbose
+	BS_FLAGS += --debug
 endif
 
+# ${sketch}.py helper script when building locally
+mock_script = \
+	`test -f $(addsuffix .py, $(basename $(1))) && echo "--mock $(addsuffix .py, $(basename $(1)))" || echo ""`
+
 help:
 	@echo
 	@echo 'make list                    - show list of tests'
 	@echo 'make sometest/sometest.ino   - run one test'
 	@echo 'make all                     - run all tests'
 	@echo 'make MOCK=1 all              - run all emulation-on-host compatible tests'
-	@echo 'variables needed: $$ARDUINO_IDE_PATH $$ESP8266_CORE_PATH'
 	@echo 'make options: V=1 NO_BUILD=1 NO_UPLOAD=1 NO_RUN=1 MOCK=1'
 	@echo
 
@@ -49,110 +69,132 @@ all: count tests test_report
 
 $(TEST_LIST): | virtualenv $(TEST_CONFIG) $(BUILD_DIR) $(HARDWARE_DIR)
 
+.NOTPARALLEL: $(TEST_LIST)
+
 tests: showtestlist $(TEST_LIST)
 
 showtestlist:
 	@echo "-------------------------------- test list:"
-	@echo $(TEST_LIST)
+	@printf '%s\n' $(TEST_LIST)
 	@echo "--------------------------------"
 
 $(TEST_LIST): LOCAL_BUILD_DIR=$(BUILD_DIR)/$(notdir $@)
-
-$(TEST_LIST):
-	@echo "--------------------------------"
-	@echo "Running test '$@' of $(words $(TEST_LIST)) tests"
-	$(SILENT)mkdir -p $(LOCAL_BUILD_DIR)
-ifeq ("$(MOCK)", "1")
-	@echo Compiling $(notdir $@)
-	(cd ../host; make D=$(V) ULIBDIRS=../device/libraries/BSTest ../device/$(@:%.ino=%))
-	$(SILENT)$(BS_DIR)/virtualenv/bin/python \
-		$(BS_DIR)/runner.py \
-			$(RUNNER_DEBUG_FLAG) \
-			-e "$(ESP8266_CORE_PATH)/tests/host/bin/$(@:%.ino=%)" \
-			-n $(basename $(notdir $@)) \
-			-o $(LOCAL_BUILD_DIR)/test_result.xml \
-			--env-file $(TEST_CONFIG) \
-			`test -f $(addsuffix .py, $(basename $@)) && echo "-m $(addsuffix .py, $(basename $@))" || echo ""`
-else
-ifneq ("$(NO_BUILD)","1")
-	@test -n "$(ARDUINO_IDE_PATH)" || (echo "Please export ARDUINO_IDE_PATH" && exit 1)
-	@echo Compiling $(notdir $@)
-	@rm -f $(LOCAL_BUILD_DIR)/build.options.json
-	$(SILENT)$(BUILD_TOOL) -compile -logger=human \
-		-libraries "$(PWD)/libraries" \
-		-core-api-version="10608" \
-		-warnings=all \
-		$(BUILDER_DEBUG_FLAG) \
-		-build-path $(LOCAL_BUILD_DIR) \
-		-tools $(ARDUINO_IDE_PATH)/tools-builder \
-		-hardware $(HARDWARE_DIR)\
-		-hardware $(ARDUINO_IDE_PATH)/hardware \
-		-fqbn=$(FQBN) \
+$(TEST_LIST): LOCAL_DATA_IMG=data.img
+
+define build-arduino
+	rm -f $(LOCAL_BUILD_DIR)/build.options.json
+	$(BUILD_TOOL) compile \
+		$(BUILD_FLAGS) \
+		--libraries "$(PWD)/libraries" \
+		--warnings=all \
+		--build-path $(LOCAL_BUILD_DIR) \
+		--fqbn=$(FQBN) \
 		$@
-endif
-ifneq ("$(NO_UPLOAD)","1")
-	@test -n "$(UPLOAD_PORT)" || (echo "Failed to detect upload port, please export UPLOAD_PORT manually" && exit 1)
-	@test -e $(dir $@)/make_spiffs.py && ( \
-		echo "Generating and uploading SPIFFS" && \
-		(cd $(dir $@) && $(PYTHON) ./make_spiffs.py $(REDIR) ) && \
-		$(MKSPIFFS) --create $(dir $@)data/ --size 0xFB000 \
-			--block 8192 --page 256 $(LOCAL_BUILD_DIR)/spiffs.img $(REDIR) && \
-		$(ESPTOOL) $(UPLOAD_VERBOSE_FLAG) \
+endef
+
+define build-mock
+	(cd $(ESP8266_CORE_PATH)/test/host; \
+		$(MAKE) D=$(V) ULIBDIRS=$(PWD)/libraries/BSTest $(PWD)/$(@:%.ino=%))
+	$(VENV_PYTHON) $(BS_DIR)/runner.py \
+		$(BS_FLAGS) \
+		--name $(basename $(notdir $@)) \
+		--output $(LOCAL_BUILD_DIR)/$(TEST_RESULT_XML) \
+		--env-file $(TEST_CONFIG) \
+		$(call mock_script,$@) \
+		executable "$(ESP8266_CORE_PATH)/tests/host/bin/$(@:%.ino=%)" || echo ""`
+endef
+
+define upload-data
+	@test -n "$(UPLOAD_PORT)" \
+		|| (echo "Failed to detect upload port, please export UPLOAD_PORT manually" && exit 1)
+	@test ! \( -d $(dir $@)/data/ \) -a \( -e $(dir $@)/make_data.py \) && \
+		(cd $(dir $@) && ./make_data.py ) || echo "Filesystem creation skipped"
+	@test -d $(dir $@)/data/ && ( \
+		$(MKFS) \
+			--create $(dir $@)/data/ \
+			--size 0xFB000 \
+			--block 8192 \
+			--page 256 \
+			$(LOCAL_BUILD_DIR)/$(LOCAL_DATA_IMG) && \
+		$(ESPTOOL) \
 			--chip esp8266 \
 			--port $(UPLOAD_PORT) \
 			--baud $(UPLOAD_BAUD) \
 			--after no_reset \
-			write_flash 0x300000 $(LOCAL_BUILD_DIR)/spiffs.img $(REDIR) ) \
-			|| (echo "No SPIFFS to upload")
-	@echo Uploading binary
-	$(SILENT)$(ESPTOOL) $(UPLOAD_VERBOSE_FLAG)  \
+			write_flash 0x300000 $(LOCAL_BUILD_DIR)/$(LOCAL_DATA_IMG) ) \
+		&& (echo "Uploaded filesystem") \
+		|| (echo "Filesystem upload skipped")
+endef
+
+define upload-binary
+	@test -n "$(UPLOAD_PORT)" \
+		|| (echo "Failed to detect upload port, please export UPLOAD_PORT manually" && exit 1)
+	$(ESPTOOL) \
 		--chip esp8266 \
 		--port $(UPLOAD_PORT) \
 		--baud $(UPLOAD_BAUD) \
 		--after no_reset \
-		write_flash 0x0 $(LOCAL_BUILD_DIR)/$(notdir $@).bin $(REDIR) # no reset
-endif
-ifneq ("$(NO_RUN)","1")
-	@test -n "$(UPLOAD_PORT)" || (echo "Failed to detect upload port, please export UPLOAD_PORT manually" && exit 1)
+		write_flash 0x0 $(LOCAL_BUILD_DIR)/$(notdir $@).bin
+endef
+
+define run-test
+	@test -n "$(UPLOAD_PORT)" \
+		|| (echo "Failed to detect upload port, please export UPLOAD_PORT manually" && exit 1)
 	@echo Running tests
-	$(SILENT)$(ESPTOOL) $(UPLOAD_VERBOSE_FLAG)  \
+	$(ESPTOOL) \
 		--chip esp8266 \
 		--port $(UPLOAD_PORT) \
 		--baud $(UPLOAD_BAUD) \
-		read_flash_status $(REDIR) # reset
-	$(SILENT)$(BS_DIR)/virtualenv/bin/python \
-		$(BS_DIR)/runner.py \
-			$(RUNNER_DEBUG_FLAG) \
-			-p $(UPLOAD_PORT) \
-			-n $(basename $(notdir $@)) \
-			-o $(LOCAL_BUILD_DIR)/test_result.xml \
-			--env-file $(TEST_CONFIG) \
-			`test -f $(addsuffix .py, $(basename $@)) && echo "-m $(addsuffix .py, $(basename $@))" || echo ""`
+		read_flash_status # reset via implicit stub reboot
+	$(VENV_PYTHON) $(BS_DIR)/runner.py \
+		$(BS_FLAGS) \
+		--name $(basename $(notdir $@)) \
+		--output $(LOCAL_BUILD_DIR)/$(TEST_RESULT_XML) \
+		--env-file $(TEST_CONFIG) \
+		$(call mock_script,$@) \
+		port $(UPLOAD_PORT) \
+		--baudrate $(TEST_BAUD)
+endef
+
+$(TEST_LIST):
+	@echo "--------------------------------"
+	@echo "Running test '$@' of $(words $(TEST_LIST)) tests"
+	mkdir -p $(LOCAL_BUILD_DIR)
+ifneq ("$(NO_BUILD)","1")
+	@echo Building $(notdir $@)
+ifeq ("$(MOCK)", "1")
+	$(build-mock)
+else
+	$(build-arduino)
 endif
 endif
+ifneq ("$(NO_UPLOAD)","1")
+	$(upload-filesystem)
+	$(upload-binary)
+endif
+ifneq ("$(NO_RUN)","1")
+	$(run-test)
+endif
 
-$(TEST_REPORT_XML): $(HARDWARE_DIR) virtualenv
-	$(SILENT)$(BS_DIR)/xunitmerge $(shell find $(BUILD_DIR) -name 'test_result.xml' | xargs echo) $(TEST_REPORT_XML)
+$(TEST_REPORT_XML): virtualenv
+	$(BS_DIR)/xunitmerge \
+		$(shell find $(BUILD_DIR) -name '$(TEST_RESULT_XML)' | xargs echo) \
+		$(TEST_REPORT_XML)
 
 $(TEST_REPORT_HTML): $(TEST_REPORT_XML) | virtualenv
-	$(SILENT)$(BS_DIR)/virtualenv/bin/junit2html $< $@
+	$(VENV_JUNIT2HTML) $< $@
 
 test_report: $(TEST_REPORT_HTML)
 	@echo "Test report generated in $(TEST_REPORT_HTML)"
 
 $(BUILD_DIR):
-	mkdir -p $(BUILD_DIR)
-
-$(HARDWARE_DIR):
-	mkdir -p $(HARDWARE_DIR)/esp8266com
-	cd $(HARDWARE_DIR)/esp8266com && ln -s $(realpath $(ESP8266_CORE_PATH)) esp8266
+	@mkdir -p $(BUILD_DIR)
 
 virtualenv:
 	@make -C $(BS_DIR) PYTHON=$(PYTHON) virtualenv
 
 clean:
 	rm -rf $(BUILD_DIR)
-	rm -rf $(HARDWARE_DIR)
 	rm -rf $(BS_DIR)/virtualenv
 	rm -f $(TEST_REPORT_HTML) $(TEST_REPORT_XML)
 
diff --git a/tests/device/libraries/BSTest/runner.py b/tests/device/libraries/BSTest/runner.py
index 5c9dddfef9..30aa93c111 100644
--- a/tests/device/libraries/BSTest/runner.py
+++ b/tests/device/libraries/BSTest/runner.py
@@ -1,40 +1,32 @@
 #!/usr/bin/env python3
-from __future__ import print_function
+
+import serial
+
 import pexpect
 from pexpect import EOF, TIMEOUT, fdpexpect
-import sys
-import os
-import time
+
+from junit_xml import TestSuite, TestCase
+
 import argparse
-import serial
+import itertools
+import os
 import subprocess
+import sys
+import time
 
+from configparser import ConfigParser
 from importlib.machinery import SourceFileLoader
+from io import StringIO
+from urllib.parse import urlparse, urlencode
 
-try:
-    from configparser import ConfigParser
-except:
-    from ConfigParser import ConfigParser
-import itertools
-try:
-    from urllib.parse import urlparse, urlencode
-except ImportError:
-    from urlparse import urlparse
-from junit_xml import TestSuite, TestCase
-try:
-    from cStringIO import StringIO
-except:
-    try:
-        from StringIO import StringIO
-    except ImportError:
-        from io import StringIO
 import mock_decorators
 
 debug = False
-#debug = True
 
 sys.path.append(os.path.abspath(__file__))
 
+IS_WSL = len(os.environ.get("WSL_DISTRO_NAME", "")) > 0
+
 def debug_print(*args, **kwargs):
     if not debug:
         return
@@ -235,9 +227,11 @@ def request_env(self, key):
 
 ser = None
 
-def spawn_port(port_name, baudrate=115200):
+def spawn_port(port_name, baudrate=115200, close=True):
     global ser
     ser = serial.serial_for_url(port_name, baudrate=baudrate)
+    if not close:
+        ser.close = lambda: None
     return fdpexpect.fdspawn(ser, 'wb', timeout=0, encoding='cp437')
 
 def spawn_exec(name):
@@ -250,30 +244,39 @@ def run_tests(spawn, name, mocks, env_vars):
 
 def parse_args():
     parser = argparse.ArgumentParser(description='BS test runner')
-    parser.add_argument('-d', '--debug', help='Send test output to stderr', action='store_true')
-    parser.add_argument('-p', '--port', help='Talk to the test over serial')
-    parser.add_argument('-e', '--executable', help='Talk to the test executable')
-    parser.add_argument('-n', '--name', help='Test run name')
-    parser.add_argument('-o', '--output', help='Output JUnit format test report')
-    parser.add_argument('-m', '--mock', help='Set python script to use for mocking purposes')
+    parser.add_argument('--debug', help='Send test output to stderr', action='store_true')
+    parser.add_argument('--name', help='Test run name')
+    parser.add_argument('--output', help='Output JUnit format test report')
+    parser.add_argument('--mock', help='Set python script to use for mocking purposes')
     parser.add_argument('--env-file', help='File containing a list of environment variables to set', type=argparse.FileType('r'))
+
+    sub = parser.add_subparsers()
+
+    def as_spawn_port(args):
+        return spawn_port(args.port, args.baudrate, args.close)
+
+    port = sub.add_parser('port')
+    port.add_argument('port', type=str)
+    port.add_argument('--baudrate', help='Serial port baudrate', type=int, default=115200)
+    port.add_argument('--close', help='Close serial port after the test', action=argparse.BooleanOptionalAction, default=not IS_WSL)
+    port.set_defaults(func=as_spawn_port)
+
+    def as_spawn_exec(args):
+        return spawn_exec(args.executable)
+
+    exe = sub.add_parser('executable')
+    exe.add_argument('executable', help='Talk to the test executable')
+    exe.set_defaults(func=as_spawn_exec)
+
     return parser.parse_args()
 
 def main():
     args = parse_args()
-    spawn_func = None
-    spawn_arg = None
-    if args.port is not None:
-        spawn_func = spawn_port
-        spawn_arg = args.port
-    elif args.executable is not None:
-        spawn_func = spawn_exec
-        spawn_arg = args.executable
+
     name = args.name or ""
     global debug
-    if args.debug:
-        debug = True
-    if spawn_func is None:
+    debug = args.debug
+    if args.func is None:
         debug_print("Please specify port or executable", file=sys.stderr)
         return 1
     env_vars = []
@@ -287,7 +290,8 @@ def main():
     if args.mock is not None:
         mocks_mod = SourceFileLoader('mocks', args.mock).load_module()
         mocks = mock_decorators.env
-    with spawn_func(spawn_arg) as sp:
+
+    with args.func(args) as sp:
         ts = run_tests(sp, name, mocks, env_vars)
         if args.output:
             with open(args.output, "w") as f:
diff --git a/tests/device/test_BearSSL/make_data.py b/tests/device/test_BearSSL/make_data.py
new file mode 120000
index 0000000000..987c479fbc
--- /dev/null
+++ b/tests/device/test_BearSSL/make_data.py
@@ -0,0 +1 @@
+../../../libraries/ESP8266WiFi/examples/BearSSL_CertStore/certs-from-mozilla.py
\ No newline at end of file
diff --git a/tests/device/test_BearSSL/make_spiffs.py b/tests/device/test_BearSSL/make_spiffs.py
deleted file mode 100755
index e423bc25b9..0000000000
--- a/tests/device/test_BearSSL/make_spiffs.py
+++ /dev/null
@@ -1,71 +0,0 @@
-#!/usr/bin/python3
-
-# This script pulls the list of Mozilla trusted certificate authorities
-# from the web at the "mozurl" below, parses the file to grab the PEM
-# for each cert, and then generates DER files in a new ./data directory
-# Upload these to a SPIFFS filesystem and use the CertManager to parse
-# and use them for your outgoing SSL connections.
-#
-# Script by Earle F. Philhower, III.  Released to the public domain.
-from __future__ import print_function
-import csv
-import os
-import sys
-from subprocess import Popen, PIPE, call
-try:
-    from urllib.request import urlopen
-except:
-    from urllib2 import urlopen
-try:
-    from StringIO import StringIO
-except:
-    from io import StringIO
-
-# Mozilla's URL for the CSV file with included PEM certs
-mozurl = "https://ccadb-public.secure.force.com/mozilla/IncludedCACertificateReportPEMCSV"
-
-# Load the manes[] and pems[] array from the URL
-names = []
-pems = []
-response = urlopen(mozurl)
-csvData = response.read()
-if sys.version_info[0] > 2:
-    csvData = csvData.decode('utf-8')
-csvFile = StringIO(csvData)
-csvReader = csv.reader(csvFile)
-for row in csvReader:
-    names.append(row[0]+":"+row[1]+":"+row[2])
-    pems.append(row[30])
-del names[0] # Remove headers
-del pems[0] # Remove headers
-
-# Try and make ./data, skip if present
-try:
-    os.mkdir("data")
-except:
-    pass
-
-derFiles = []
-idx = 0
-# Process the text PEM using openssl into DER files
-for i in range(0, len(pems)):
-    certName = "data/ca_%03d.der" % (idx);
-    thisPem = pems[i].replace("'", "")
-    print(names[i] + " -> " + certName)
-    ssl = Popen(['openssl','x509','-inform','PEM','-outform','DER','-out', certName], shell = False, stdin = PIPE)
-    pipe = ssl.stdin
-    pipe.write(thisPem.encode('utf-8'))
-    pipe.close()
-    ssl.wait()
-    if os.path.exists(certName):
-        derFiles.append(certName)
-        idx = idx + 1
-
-if os.path.exists("data/certs.ar"):
-    os.unlink("data/certs.ar");
-
-arCmd = ['ar', 'q', 'data/certs.ar'] + derFiles;
-call( arCmd )
-
-for der in derFiles:
-    os.unlink(der)
diff --git a/tests/device/test_BearSSL/test_BearSSL.ino b/tests/device/test_BearSSL/test_BearSSL.ino
index e4db2fdc0e..73ab226524 100644
--- a/tests/device/test_BearSSL/test_BearSSL.ino
+++ b/tests/device/test_BearSSL/test_BearSSL.ino
@@ -1,7 +1,7 @@
 // Stress test the BearSSL connection options to determine
 // maximum memory use for different SSL connections and
-// SPIFFS certstore usage.  Before running you need to run
-// certs-from-mozilla.py and upload the generated SPIFFS file.
+// filesystem certstore usage.  Before running the test you need to
+// update them with certs-from-mozilla.py and upload the generated file.
 //
 // For more info on CertStores, see the BearSSL_CertStore example
 //
@@ -12,7 +12,7 @@
 #include <BSTest.h>
 #include <ESP8266WiFi.h>
 #include <CertStoreBearSSL.h>
-#include <FS.h>
+#include <LittleFS.h>
 #include <time.h>
 #include <StackThunk.h>
 
@@ -45,11 +45,11 @@ bool pretest()
         delay(500);
     }
     setClock();
-    SPIFFS.begin();
-    int numCerts = certStore.initCertStore(SPIFFS, "/certs.idx", "/certs.ar");
+    LittleFS.begin();
+    int numCerts = certStore.initCertStore(LittleFS, "/certs.idx", "/certs.ar");
     Serial.printf("Number of CA certs read: %d\n", numCerts);
     if (numCerts == 0) {
-        Serial.printf("No certs found. Did you run certs-from-mozill.py and upload the SPIFFS directory before running?\n");
+        Serial.printf("No certs found. Did you run upload script?\n");
         return false;
     }
     return true;
diff --git a/tests/device/test_libc/libm_string.c b/tests/device/test_libc/libm_string.c
index 9a19da58a4..dd464fbd46 100644
--- a/tests/device/test_libc/libm_string.c
+++ b/tests/device/test_libc/libm_string.c
@@ -3,51 +3,130 @@
 #include <stdlib.h>
 #include <errno.h>
 
-#define memcmp memcmp_P
-#define memcpy memcpy_P
-#define memmem memmem_P
-#define memchr memchr_P
-#define strcat strcat_P
-#define strncat strncat_P
-#define strcpy strcpy_P
-#define strncpy strncpy_P
-#define strlen strlen_P
-#define strnlen strnlen_P
-#define strcmp strcmp_P
-#define strncmp strncmp_P
-
-_CONST char* it     = "<UNSET>"; /* Routine name for message routines. */
+#include <sys/pgmspace.h>
+
+/* esp8266/Arduino note
+ *
+ * Prevent the compiler from
+ * - solving test cases below at compile time, effectively removing any checks
+ * - optimizing out libc func calls, replacing them with bytewise memory access
+ *
+ * Plus, test framework cannot pass -fno-builtin-... per-file, only globally
+ */
+
+#define xDST_SRC_N(T, NAME)\
+static T* __attribute__((used, noinline)) x ## NAME (T* dst, const T* src, size_t n)\
+{\
+    return NAME (dst, src, n);\
+}
+
+xDST_SRC_N (void, memcpy)
+xDST_SRC_N (void, memmove)
+xDST_SRC_N (char, strncat)
+xDST_SRC_N (char, strncpy)
+
+#define xDST_SRC(T, NAME)\
+static T* __attribute__((used, noinline)) x ## NAME (T* dst, const T* src)\
+{\
+    return NAME (dst, src);\
+}
+
+xDST_SRC (char, strcat)
+xDST_SRC (char, strcpy)
+
+#define xS1_S2_N(RET, T, NAME)\
+static RET __attribute__((used, noinline)) x ## NAME (const T *s1, const T *s2, size_t n)\
+{\
+    return NAME (s1, s2, n);\
+}
+
+xS1_S2_N(int, void, memcmp)
+xS1_S2_N(int, char, strncmp)
+
+static int __attribute__((used, noinline)) xstrcmp (const char *s1, const char *s2)
+{
+    return strcmp (s1, s2);
+}
+
+static void* __attribute__((used, noinline)) xmemchr (const void* s, int c, size_t n)
+{
+    return memchr (s, c, n);
+}
+
+static size_t __attribute__((used, noinline)) xstrlen (const char* s)
+{
+    return strlen (s);
+}
+
+#if 0
+
+/* TODO remove when libc supports pointers to flash */
+#undef PSTR
+#define PSTR(X) X
+
+#define memcmp(s1,s2,n) xmemcmp(s1,PSTR(s2),n)
+#define memcpy(dest,src,n) xmemcpy(dest,PSTR(src),n)
+#define memmove(dest,src,n) xmemmove(dest,PSTR(src),n)
+#define memchr(s,c,n) xmemchr(PSTR(s),c,n)
+#define strcat(dst,src) xstrcat(dst,PSTR(src))
+#define strncat(dst,src,ssize) xstrncat(dst,PSTR(src),ssize)
+#define strcpy(dst,src) xstrcpy(dst,PSTR(src))
+#define strncpy(dst,src,dsize) xstrncpy(dst,PSTR(src),dsize)
+#define strlen(s) xstrlen(PSTR(s))
+#define strcmp(s1,s2) xstrcmp(s1,PSTR(s2))
+#define strncmp(s1,s2,n) xstrncmp(s1,PSTR(s2),n)
+
+#else
+
+/* in case wrapped calls are not required */
+
+#define memcmp(s1,s2,n) memcmp_P(s1,PSTR(s2),n)
+#define memcpy(dest,src,n) memcpy_P(dest,PSTR(src),n)
+#define memmove(dest,src,n) memmove_P(dest,PSTR(src),n)
+#define memchr(s,c,n) memchr_P(PSTR(s),c,n)
+#define strcat(dst,src) strcat_P(dst,PSTR(src))
+#define strncat(dst,src,ssize) strncat_P(dst,PSTR(src),ssize)
+#define strcpy(dst,src) strcpy_P(dst,PSTR(src))
+#define strncpy(dst,src,dsize) strncpy_P(dst,PSTR(src),dsize)
+#define strlen(s) strlen_P(PSTR(s))
+#define strcmp(s1,s2) strcmp_P(s1,PSTR(s2))
+#define strncmp(s1,s2,n) strncmp_P(s1,PSTR(s2),n)
+
+#endif
+
+static const char Unset[] PROGMEM = "<UNSET>";
+
+const char* it      = Unset; /* Routine name for message routines. */
 static int   errors = 0;
 
 /* Complain if condition is not true.  */
 #define check(thing) checkit(thing, __LINE__)
 
-static void _DEFUN(checkit, (ok, l), int ok _AND int l)
-
+static void checkit(int ok, int l)
 {
     //  newfunc(it);
     //  line(l);
 
     if (!ok)
     {
-        printf("string.c:%d %s\n", l, it);
+        printf(PSTR("string.c:%d %s\n"), l, it);
         ++errors;
     }
 }
 
 /* Complain if first two args don't strcmp as equal.  */
-#define equal(a, b) funcqual(a, b, __LINE__);
+#define equal(a, b) funcqual(a, PSTR(b), __LINE__);
 
-static void _DEFUN(funcqual, (a, b, l), char* a _AND char* b _AND int l)
+static void funcqual(const char *a, const char *b, int l)
 {
     //  newfunc(it);
 
     //  line(l);
     if (a == NULL && b == NULL)
         return;
-    if (strcmp(a, b))
+    if (strcmp_P(a, b))
     {
-        printf("string.c:%d (%s)\n", l, it);
+        printf(PSTR("string.c:%d (%s)\n"), l, it);
     }
 }
 
@@ -57,7 +136,7 @@ static char two[50];
 void libm_test_string()
 {
     /* Test strcmp first because we use it to test other things.  */
-    it = "strcmp";
+    it = PSTR("strcmp");
     check(strcmp("", "") == 0);       /* Trivial case. */
     check(strcmp("a", "a") == 0);     /* Identity. */
     check(strcmp("abc", "abc") == 0); /* Multicharacter. */
@@ -69,7 +148,7 @@ void libm_test_string()
     check(strcmp("a\103", "a\003") > 0);
 
     /* Test strcpy next because we need it to set up other tests.  */
-    it = "strcpy";
+    it = PSTR("strcpy");
     check(strcpy(one, "abcd") == one); /* Returned value. */
     equal(one, "abcd");                /* Basic test. */
 
@@ -78,7 +157,7 @@ void libm_test_string()
     equal(one + 2, "cd"); /* Wrote too much? */
 
     (void)strcpy(two, "hi there");
-    (void)strcpy(one, two);
+    (void)xstrcpy(one, two);
     equal(one, "hi there"); /* Basic test encore. */
     equal(two, "hi there"); /* Stomped on source? */
 
@@ -86,7 +165,7 @@ void libm_test_string()
     equal(one, ""); /* Boundary condition. */
 
     /* strcat.  */
-    it = "strcat";
+    it = PSTR("strcat");
     (void)strcpy(one, "ijk");
     check(strcat(one, "lmn") == one); /* Returned value. */
     equal(one, "ijklmn");             /* Basic test. */
@@ -98,7 +177,7 @@ void libm_test_string()
 
     (void)strcpy(one, "gh");
     (void)strcpy(two, "ef");
-    (void)strcat(one, two);
+    (void)xstrcpy(one, two);
     equal(one, "ghef"); /* Basic test encore. */
     equal(two, "ef");   /* Stomped on source? */
 
@@ -114,42 +193,67 @@ void libm_test_string()
 
     /* strncat - first test it as strcat, with big counts,
        then test the count mechanism.  */
-    it = "strncat";
+    it = PSTR("strncat");
     (void)strcpy(one, "ijk");
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wstringop-overflow="
     check(strncat(one, "lmn", 99) == one); /* Returned value. */
+#pragma GCC diagnostic pop
     equal(one, "ijklmn");                  /* Basic test. */
 
     (void)strcpy(one, "x");
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wstringop-overflow="
     (void)strncat(one, "yz", 99);
+#pragma GCC diagnostic pop
     equal(one, "xyz");    /* Writeover. */
     equal(one + 4, "mn"); /* Wrote too much? */
 
     (void)strcpy(one, "gh");
     (void)strcpy(two, "ef");
-    (void)strncat(one, two, 99);
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Warray-bounds="
+#pragma GCC diagnostic ignored "-Wstringop-overflow="
+    (void)xstrncat(one, two, 99);
+#pragma GCC diagnostic pop
     equal(one, "ghef"); /* Basic test encore. */
     equal(two, "ef");   /* Stomped on source? */
 
     (void)strcpy(one, "");
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wstringop-overflow="
     (void)strncat(one, "", 99);
+#pragma GCC diagnostic pop
     equal(one, ""); /* Boundary conditions. */
     (void)strcpy(one, "ab");
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wstringop-overflow="
     (void)strncat(one, "", 99);
+#pragma GCC diagnostic pop
     equal(one, "ab");
     (void)strcpy(one, "");
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wstringop-overflow="
     (void)strncat(one, "cd", 99);
+#pragma GCC diagnostic pop
     equal(one, "cd");
 
     (void)strcpy(one, "ab");
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wstringop-truncation"
     (void)strncat(one, "cdef", 2);
+#pragma GCC diagnostic pop
     equal(one, "abcd"); /* Count-limited. */
 
     (void)strncat(one, "gh", 0);
     equal(one, "abcd"); /* Zero count. */
 
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wstringop-overflow"
     (void)strncat(one, "gh", 2);
+#pragma GCC diagnostic pop
     equal(one, "abcdgh"); /* Count _AND length equal. */
-    it = "strncmp";
+    it = PSTR("strncmp");
     /* strncmp - first test as strcmp with big counts";*/
     check(strncmp("", "", 99) == 0);       /* Trivial case. */
     check(strncmp("a", "a", 99) == 0);     /* Identity. */
@@ -164,16 +268,22 @@ void libm_test_string()
     check(strncmp("abc", "def", 0) == 0);   /* Zero count. */
 
     /* strncpy - testing is a bit different because of odd semantics.  */
-    it = "strncpy";
+    it = PSTR("strncpy");
     check(strncpy(one, "abc", 4) == one); /* Returned value. */
     equal(one, "abc");                    /* Did the copy go right? */
 
     (void)strcpy(one, "abcdefgh");
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wstringop-truncation"
     (void)strncpy(one, "xyz", 2);
+#pragma GCC diagnostic pop
     equal(one, "xycdefgh"); /* Copy cut by count. */
 
     (void)strcpy(one, "abcdefgh");
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wstringop-truncation"
     (void)strncpy(one, "xyz", 3); /* Copy cut just before NUL. */
+#pragma GCC diagnostic pop
     equal(one, "xyzdefgh");
 
     (void)strcpy(one, "abcdefgh");
@@ -188,7 +298,10 @@ void libm_test_string()
     equal(one + 5, "fgh");
 
     (void)strcpy(one, "abc");
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wstringop-truncation"
     (void)strncpy(one, "xyz", 0); /* Zero-length copy. */
+#pragma GCC diagnostic pop
     equal(one, "abc");
 
     (void)strncpy(one, "", 2); /* Zero-length source. */
@@ -197,18 +310,18 @@ void libm_test_string()
     equal(one + 2, "c");
 
     (void)strcpy(one, "hi there");
-    (void)strncpy(two, one, 9);
+    (void)xstrncpy(two, one, 9);
     equal(two, "hi there"); /* Just paranoia. */
     equal(one, "hi there"); /* Stomped on source? */
 
     /* strlen.  */
-    it = "strlen";
+    it = PSTR("strlen");
     check(strlen("") == 0);     /* Empty. */
     check(strlen("a") == 1);    /* Single char. */
     check(strlen("abcd") == 4); /* Multiple chars. */
 
     /* strchr.  */
-    it = "strchr";
+    it = PSTR("strchr");
     check(strchr("abcd", 'z') == NULL); /* Not found. */
     (void)strcpy(one, "abcd");
     check(strchr(one, 'c') == one + 2);  /* Basic test. */
@@ -222,7 +335,7 @@ void libm_test_string()
     check(strchr(one, '\0') == one); /* NUL in empty string. */
 
     /* index - just like strchr.  */
-    it = "index";
+    it = PSTR("index");
     check(index("abcd", 'z') == NULL); /* Not found. */
     (void)strcpy(one, "abcd");
     check(index(one, 'c') == one + 2);  /* Basic test. */
@@ -236,7 +349,7 @@ void libm_test_string()
     check(index(one, '\0') == one); /* NUL in empty string. */
 
     /* strrchr.  */
-    it = "strrchr";
+    it = PSTR("strrchr");
     check(strrchr("abcd", 'z') == NULL); /* Not found. */
     (void)strcpy(one, "abcd");
     check(strrchr(one, 'c') == one + 2);  /* Basic test. */
@@ -250,7 +363,7 @@ void libm_test_string()
     check(strrchr(one, '\0') == one); /* NUL in empty string. */
 
     /* rindex - just like strrchr.  */
-    it = "rindex";
+    it = PSTR("rindex");
     check(rindex("abcd", 'z') == NULL); /* Not found. */
     (void)strcpy(one, "abcd");
     check(rindex(one, 'c') == one + 2);  /* Basic test. */
@@ -264,7 +377,7 @@ void libm_test_string()
     check(rindex(one, '\0') == one); /* NUL in empty string. */
 
     /* strpbrk - somewhat like strchr.  */
-    it = "strpbrk";
+    it = PSTR("strpbrk");
     check(strpbrk("abcd", "z") == NULL); /* Not found. */
     (void)strcpy(one, "abcd");
     check(strpbrk(one, "c") == one + 2);  /* Basic test. */
@@ -281,7 +394,7 @@ void libm_test_string()
     check(strpbrk(one, "") == NULL);   /* Both strings empty. */
 
     /* strstr - somewhat like strchr.  */
-    it = "strstr";
+    it = PSTR("strstr");
     check(strstr("z", "abcd") == NULL);   /* Not found. */
     check(strstr("abx", "abcd") == NULL); /* Dead end. */
     (void)strcpy(one, "abcd");
@@ -304,7 +417,7 @@ void libm_test_string()
     check(strstr(one, "bbca") == one + 1); /* With overlap. */
 
     /* strspn.  */
-    it = "strspn";
+    it = PSTR("strspn");
     check(strspn("abcba", "abc") == 5); /* Whole string. */
     check(strspn("abcba", "ab") == 2);  /* Partial. */
     check(strspn("abc", "qx") == 0);    /* None. */
@@ -312,7 +425,7 @@ void libm_test_string()
     check(strspn("abc", "") == 0);      /* Null search list. */
 
     /* strcspn.  */
-    it = "strcspn";
+    it = PSTR("strcspn");
     check(strcspn("abcba", "qx") == 5); /* Whole string. */
     check(strcspn("abcba", "cx") == 2); /* Partial. */
     check(strcspn("abc", "abc") == 0);  /* None. */
@@ -320,7 +433,7 @@ void libm_test_string()
     check(strcspn("abc", "") == 3);     /* Null search list. */
 
     /* strtok - the hard one.  */
-    it = "strtok";
+    it = PSTR("strtok");
     (void)strcpy(one, "first, second, third");
     equal(strtok(one, ", "), "first"); /* Basic test. */
     equal(one, "first");
@@ -367,7 +480,7 @@ void libm_test_string()
     equal(one + 4, "c");
 
     /* memcmp.  */
-    it = "memcmp";
+    it = PSTR("memcmp");
     check(memcmp("a", "a", 1) == 0);      /* Identity. */
     check(memcmp("abc", "abc", 3) == 0);  /* Multicharacter. */
     check(memcmp("abcd", "abce", 4) < 0); /* Honestly unequal. */
@@ -379,25 +492,25 @@ void libm_test_string()
     /* memcmp should test strings as unsigned */
     one[0] = 0xfe;
     two[0] = 0x03;
-    check(memcmp(one, two, 1) > 0);
+    check(xmemcmp(one, two, 1) > 0);
 
     /* memchr.  */
-    it = "memchr";
+    it = PSTR("memchr");
     check(memchr("abcd", 'z', 4) == NULL); /* Not found. */
     (void)strcpy(one, "abcd");
-    check(memchr(one, 'c', 4) == one + 2);  /* Basic test. */
-    check(memchr(one, 'd', 4) == one + 3);  /* End of string. */
-    check(memchr(one, 'a', 4) == one);      /* Beginning. */
-    check(memchr(one, '\0', 5) == one + 4); /* Finding NUL. */
+    check(xmemchr(one, 'c', 4) == one + 2);  /* Basic test. */
+    check(xmemchr(one, 'd', 4) == one + 3);  /* End of string. */
+    check(xmemchr(one, 'a', 4) == one);      /* Beginning. */
+    check(xmemchr(one, '\0', 5) == one + 4); /* Finding NUL. */
     (void)strcpy(one, "ababa");
-    check(memchr(one, 'b', 5) == one + 1); /* Finding first. */
-    check(memchr(one, 'b', 0) == NULL);    /* Zero count. */
-    check(memchr(one, 'a', 1) == one);     /* Singleton case. */
+    check(xmemchr(one, 'b', 5) == one + 1); /* Finding first. */
+    check(xmemchr(one, 'b', 0) == NULL);    /* Zero count. */
+    check(xmemchr(one, 'a', 1) == one);     /* Singleton case. */
     (void)strcpy(one, "a\203b");
-    check(memchr(one, 0203, 3) == one + 1); /* Unsignedness. */
+    check(xmemchr(one, 0203, 3) == one + 1); /* Unsignedness. */
 
     /* memcpy - need not work for overlap.  */
-    it = "memcpy";
+    it = PSTR("memcpy");
     check(memcpy(one, "abc", 4) == one); /* Returned value. */
     equal(one, "abc");                   /* Did the copy go right? */
 
@@ -411,13 +524,13 @@ void libm_test_string()
 
     (void)strcpy(one, "hi there");
     (void)strcpy(two, "foo");
-    (void)memcpy(two, one, 9);
+    (void)xmemcpy(two, one, 9);
     equal(two, "hi there"); /* Just paranoia. */
     equal(one, "hi there"); /* Stomped on source? */
-#if 0
+#if 1
   /* memmove - must work on overlap.  */
-  it = "memmove";
-  check(memmove(one, "abc", 4) == one); /* Returned value. */
+  it = PSTR("memmove");
+  check(xmemmove(one, "abc", 4) == one); /* Returned value. */
   equal(one, "abc");		/* Did the copy go right? */
 
   (void) strcpy(one, "abcdefgh");
@@ -430,20 +543,20 @@ void libm_test_string()
 
   (void) strcpy(one, "hi there");
   (void) strcpy(two, "foo");
-  (void) memmove(two, one, 9);
+  (void) xmemmove(two, one, 9);
   equal(two, "hi there");	/* Just paranoia. */
   equal(one, "hi there");	/* Stomped on source? */
 
   (void) strcpy(one, "abcdefgh");
-  (void) memmove(one+1, one, 9);
+  (void) xmemmove(one+1, one, 9);
   equal(one, "aabcdefgh");	/* Overlap, right-to-left. */
 
   (void) strcpy(one, "abcdefgh");
-  (void) memmove(one+1, one+2, 7);
+  (void) xmemmove(one+1, one+2, 7);
   equal(one, "acdefgh");	/* Overlap, left-to-right. */
 
   (void) strcpy(one, "abcdefgh");
-  (void) memmove(one, one, 9);
+  (void) xmemmove(one, one, 9);
   equal(one, "abcdefgh");	/* 100% overlap. */
 #endif
 #if 0
@@ -451,7 +564,7 @@ void libm_test_string()
      The SVID, the only place where memccpy is mentioned, says
      overlap might fail, so we don't try it.  Besides, it's hard
      to see the rationale for a non-left-to-right memccpy.  */
-  it = "memccpy";
+  it = PSTR("memccpy");
   check(memccpy(one, "abc", 'q', 4) == NULL); /* Returned value. */
   equal(one, "abc");		/* Did the copy go right? */
 
@@ -486,12 +599,15 @@ void libm_test_string()
   equal(two, "xbcdlebee");
 #endif
     /* memset.  */
-    it = "memset";
+    it = PSTR("memset");
     (void)strcpy(one, "abcdefgh");
     check(memset(one + 1, 'x', 3) == one + 1); /* Return value. */
     equal(one, "axxxefgh");                    /* Basic test. */
 
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wmemset-transposed-args"
     (void)memset(one + 2, 'y', 0);
+#pragma GCC diagnostic pop
     equal(one, "axxxefgh"); /* Zero-length set. */
 
     (void)memset(one + 5, 0, 1);
@@ -503,7 +619,7 @@ void libm_test_string()
 
     /* bcopy - much like memcpy.
        Berklix manual is silent about overlap, so don't test it.  */
-    it = "bcopy";
+    it = PSTR("bcopy");
     (void)bcopy("abc", one, 4);
     equal(one, "abc"); /* Simple copy. */
 
@@ -522,7 +638,7 @@ void libm_test_string()
     equal(one, "hi there"); /* Stomped on source? */
 
     /* bzero.  */
-    it = "bzero";
+    it = PSTR("bzero");
     (void)strcpy(one, "abcdef");
     bzero(one + 2, 2);
     equal(one, "ab"); /* Basic test. */
@@ -534,7 +650,7 @@ void libm_test_string()
     equal(one, "abcdef"); /* Zero-length copy. */
 
     /* bcmp - somewhat like memcmp.  */
-    it = "bcmp";
+    it = PSTR("bcmp");
     check(bcmp("a", "a", 1) == 0);       /* Identity. */
     check(bcmp("abc", "abc", 3) == 0);   /* Multicharacter. */
     check(bcmp("abcd", "abce", 4) != 0); /* Honestly unequal. */
diff --git a/tests/device/test_libc/memmove1.c b/tests/device/test_libc/memmove1.c
index 8a6403ee94..8e357002d9 100644
--- a/tests/device/test_libc/memmove1.c
+++ b/tests/device/test_libc/memmove1.c
@@ -62,6 +62,7 @@ int errors = 0;
     printf
 
 /* A safe target-independent memmove.  */
+void mymemmove(unsigned char* dest, unsigned char* src, size_t n) __attribute__((__noinline__));
 
 void mymemmove(unsigned char* dest, unsigned char* src, size_t n)
 {
diff --git a/tests/device/test_libc/strcmp-1.c b/tests/device/test_libc/strcmp-1.c
index e8663b9ba9..b76324a92e 100644
--- a/tests/device/test_libc/strcmp-1.c
+++ b/tests/device/test_libc/strcmp-1.c
@@ -31,18 +31,8 @@
 #include <stdio.h>
 #include <stdarg.h>
 
-#define memcmp memcmp_P
 #define memcpy memcpy_P
-#define memmem memmem_P
-#define memchr memchr_P
-#define strcat strcat_P
-#define strncat strncat_P
-#define strcpy strcpy_P
-#define strncpy strncpy_P
-#define strlen strlen_P
-#define strnlen strnlen_P
 #define strcmp strcmp_P
-#define strncmp strncmp_P
 
 #define BUFF_SIZE 256
 
diff --git a/tests/device/test_libc/test_libc.ino.globals.h b/tests/device/test_libc/test_libc.ino.globals.h
new file mode 100644
index 0000000000..1bfe3ba4d5
--- /dev/null
+++ b/tests/device/test_libc/test_libc.ino.globals.h
@@ -0,0 +1,4 @@
+/*@create-file:build.opt@
+
+-fno-builtin
+*/
diff --git a/tests/device/test_libc/tstring.c b/tests/device/test_libc/tstring.c
index 7d508d4c6e..43adfc3bed 100644
--- a/tests/device/test_libc/tstring.c
+++ b/tests/device/test_libc/tstring.c
@@ -13,6 +13,7 @@
 #define MAX_1 50
 #define memcmp memcmp_P
 #define memcpy memcpy_P
+#define memmove memmove_P
 #define memmem memmem_P
 #define memchr memchr_P
 #define strcat strcat_P
@@ -86,6 +87,8 @@ void tstring_main(void)
     tmp2[0] = 'Z';
     tmp2[1] = '\0';
 
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wmemset-transposed-args"
     if (memset(target, 'X', 0) != target || memcpy(target, "Y", 0) != target
         || memmove(target, "K", 0) != target || strncpy(tmp2, "4", 0) != tmp2
         || strncat(tmp2, "123", 0) != tmp2 || strcat(target, "") != target)
@@ -93,6 +96,7 @@ void tstring_main(void)
         eprintf(__LINE__, target, "A", 0);
         test_failed = 1;
     }
+#pragma GCC diagnostic pop
 
     if (strcmp(target, "A") || strlen(target) != 1 || memchr(target, 'A', 0) != NULL
         || memcmp(target, "J", 0) || strncmp(target, "A", 1) || strncmp(target, "J", 0)
diff --git a/tests/device/test_sw_FS/test_sw_FS.ino b/tests/device/test_sw_FS/test_sw_FS.ino
index 0a33dc8586..41d7d188fc 100644
--- a/tests/device/test_sw_FS/test_sw_FS.ino
+++ b/tests/device/test_sw_FS/test_sw_FS.ino
@@ -1,5 +1,5 @@
 #include <ESP8266WiFi.h>
-#include "FS.h"
+#include <LittleFS.h>
 #include <BSTest.h>
 
 BS_ENV_DECLARE();
@@ -18,17 +18,17 @@ bool pretest()
 
 TEST_CASE("read-write test","[fs]")
 {
-    REQUIRE(SPIFFS.begin());
+    REQUIRE(LittleFS.begin());
 
     String text = "write test";
     {
-        File out = SPIFFS.open("/tmp.txt", "w");
+        File out = LittleFS.open("/tmp.txt", "w");
         REQUIRE(out);
         out.print(text);
     }
 
     {
-        File in = SPIFFS.open("/tmp.txt", "r");
+        File in = LittleFS.open("/tmp.txt", "r");
         REQUIRE(in);
         CHECK(in.size() == text.length());
         in.setTimeout(0);
@@ -39,14 +39,14 @@ TEST_CASE("read-write test","[fs]")
 
 TEST_CASE("A bunch of files show up in openDir, and can be removed", "[fs]")
 {
-    REQUIRE(SPIFFS.begin());
+    REQUIRE(LittleFS.begin());
     const int n = 10;
     int found[n] = {0};
 
     {
-        Dir root = SPIFFS.openDir("");
+        Dir root = LittleFS.openDir("");
         while (root.next()) {
-            CHECK(SPIFFS.remove(root.fileName()));
+            CHECK(LittleFS.remove(root.fileName()));
         }
     }
 
@@ -55,14 +55,14 @@ TEST_CASE("A bunch of files show up in openDir, and can be removed", "[fs]")
         name += i;
         name += ".txt";
 
-        File out = SPIFFS.open(name, "w");
+        File out = LittleFS.open(name, "w");
         REQUIRE(out);
 
         out.println(i);
     }
 
     {
-        Dir root = SPIFFS.openDir("/");
+        Dir root = LittleFS.openDir("/");
         while (root.next()) {
             String fileName = root.fileName();
             CHECK(fileName.indexOf("/seq_") == 0);
@@ -77,35 +77,35 @@ TEST_CASE("A bunch of files show up in openDir, and can be removed", "[fs]")
     }
 
     {
-        Dir root = SPIFFS.openDir("/");
+        Dir root = LittleFS.openDir("/");
         while (root.next()) {
             String fileName = root.fileName();
-            CHECK(SPIFFS.remove(fileName));
+            CHECK(LittleFS.remove(fileName));
         }
     }
 }
 
 TEST_CASE("files can be renamed", "[fs]")
 {
-    REQUIRE(SPIFFS.begin());
+    REQUIRE(LittleFS.begin());
     {
-        File tmp = SPIFFS.open("/tmp1.txt", "w");
+        File tmp = LittleFS.open("/tmp1.txt", "w");
         tmp.println("rename test");
     }
 
     {
-        CHECK(SPIFFS.rename("/tmp1.txt", "/tmp2.txt"));
+        CHECK(LittleFS.rename("/tmp1.txt", "/tmp2.txt"));
 
-        File tmp2 = SPIFFS.open("/tmp2.txt", "r");
+        File tmp2 = LittleFS.open("/tmp2.txt", "r");
         CHECK(tmp2);
     }
 }
 
 TEST_CASE("FS::info works","[fs]")
 {
-    REQUIRE(SPIFFS.begin());
+    REQUIRE(LittleFS.begin());
     FSInfo info;
-    CHECK(SPIFFS.info(info));
+    CHECK(LittleFS.info(info));
 
     Serial.printf("Total: %u\nUsed: %u\nBlock: %u\nPage: %u\nMax open files: %u\nMax path len: %u\n",
                   info.totalBytes,
@@ -119,10 +119,10 @@ TEST_CASE("FS::info works","[fs]")
 
 TEST_CASE("FS is empty after format","[fs]")
 {
-    REQUIRE(SPIFFS.begin());
-    REQUIRE(SPIFFS.format());
+    REQUIRE(LittleFS.begin());
+    REQUIRE(LittleFS.format());
 
-    Dir root = SPIFFS.openDir("/");
+    Dir root = LittleFS.openDir("/");
     int count = 0;
     while (root.next()) {
         ++count;
@@ -132,12 +132,12 @@ TEST_CASE("FS is empty after format","[fs]")
 
 TEST_CASE("Can reopen empty file","[fs]")
 {
-    REQUIRE(SPIFFS.begin());
+    REQUIRE(LittleFS.begin());
     {
-        File tmp = SPIFFS.open("/tmp.txt", "w");
+        File tmp = LittleFS.open("/tmp.txt", "w");
     }
     {
-        File tmp = SPIFFS.open("/tmp.txt", "w");
+        File tmp = LittleFS.open("/tmp.txt", "w");
         CHECK(tmp);
     }
 }
diff --git a/tests/restyle.py b/tests/restyle.py
index 78a8816000..4be9cab555 100755
--- a/tests/restyle.py
+++ b/tests/restyle.py
@@ -85,6 +85,7 @@ def find_core_files():
         )
         if file.is_file()
         and file.suffix in (".c", ".cpp", ".h", ".hpp")
+        and not GIT_ROOT / "tests/device/test_libc" in file.parents
         and not GIT_ROOT / "tests/host/bin" in file.parents
         and not GIT_ROOT / "tests/host/common/catch.hpp" == file
     ]