legacy+core: accept only valid UTF-8 strings via nanopb

core/SConscript.bootloader

@@ -155,6 +155,8 @@ env.Replace(
         'USE_HAL_DRIVER',
         ('STM32_HAL_H', '"<stm32f4xx.h>"'),
         'PB_FIELD_16BIT',
+        'PB_ENCODE_ARRAYS_UNPACKED',
+        'PB_VALIDATE_UTF8',
     ] + CPPDEFINES_MOD,
     ASFLAGS=CPU_ASFLAGS,
     ASPPFLAGS='$CFLAGS $CCFLAGS', )

legacy/firmware/Makefile

@@ -125,7 +125,7 @@ DEBUG_LINK ?= 0
 DEBUG_LOG  ?= 0
 
 CFLAGS += -Wno-sequence-point
-CFLAGS += -I../vendor/nanopb -Iprotob -DPB_FIELD_16BIT=1 -DPB_ENCODE_ARRAYS_UNPACKED=1
+CFLAGS += -I../vendor/nanopb -Iprotob -DPB_FIELD_16BIT=1 -DPB_ENCODE_ARRAYS_UNPACKED=1 -DPB_VALIDATE_UTF8=1
 CFLAGS += -DDEBUG_LINK=$(DEBUG_LINK)
 CFLAGS += -DDEBUG_LOG=$(DEBUG_LOG)
 CFLAGS += -DSCM_REVISION='"$(shell git rev-parse HEAD | sed 's:\(..\):\\x\1:g')"'