nRF52840DK build error: src/jslex.o make: *** [espruino_2v08.220_nrf52840.elf] Error 1

Wow, and this sequence worked:

make clean make

BOARD=NRF52840DK make

src/jsutils.c:374:3: note: called from here
   NVIC_SystemReset();
   ^
/mnt/c/Users/robin/Espruino/targetlibs/nrf5x_15/components/toolchain/cmsis/include/core_cm4.h:1790:22: warning: inlining failed in call to 'NVIC_SystemReset': call is unlikely and code size would grow [-Winline]
 __STATIC_INLINE void NVIC_SystemReset(void)
                      ^
src/jsutils.c:374:3: note: called from here
   NVIC_SystemReset();
   ^
python scripts/check_elf_size.py NRF52840DK espruino_2v08.220_nrf52840.elf
Testing espruino_2v08.220_nrf52840.elf for NRF52840DK
STORAGE: 966656 -> 1007616
FS DATA: 492980 -> 493000 (20 bytes)
CODE: 155648 -> 493000 (336136 bytes)
Code area Fits before Storage Area
arm-none-eabi-objcopy -O ihex espruino_2v08.220_nrf52840.elf espruino_2v08.220_nrf52840.hex        
Merging SoftDevice
python scripts/hexmerge.py /mnt/c/Users/robin/Espruino/targetlibs/nrf5x_15/components/softdevice/s140/hex/s140_nrf52_6.0.0_softdevice.hex espruino_2v08.220_nrf52840.app_hex -o espruino_2v08.220_nrf52840.hex
rgc@DESKTOP-R7T0VUC:/mnt/c/Users/robin/Espruino$

Fianlly, espruino_2v08.220_nrf52840.elf and espruino_2v08.220_nrf52840.hex get built!

I have no explanation other than I removed the RELEASE=1 part and cleaned in separate steps:

make clean make

BOARD=NRF52840DK make

vs

make clean && BOARD=NRF52840DK RELEASE=1 make