Hi @tve,

Latest build seems to use espressif sdk 1.5, but README gives a command example for 1.4(b1):

ceremcem@cca-erik:espruino_1v86.tve_master_8d2f1b4_esp8266$ ls
blank.bin boot_v1.5.bin esp_init_data_default.bin espruino_esp8266_user1.bin >espruino_esp8266_user2.bin README_flash.txt wiflash.sh
ceremcem@cca-erik:espruino_1v86.tve_master_8d2f1b4_esp8266$ cat README_flash.txt

How to flash Espruino esp8266

*** To flash a 512KB esp8266 (e.g. esp-01) using the serial port use:
esptool.py --port [/dev/ttyUSB0|COM1] --baud 460800 write_flash \
--flash_freq 40m --flash_mode qio --flash_size 4m \
0x0000 "boot_v1.4(b1).bin" 0x1000 espruino_esp8266_user1.bin 0x7E000 blank.bin

*** To flash a 4MB esp8266 (e.g. esp-12) using the serial port use:
esptool.py --port [/dev/ttyUSB0|COM1] --baud 460800 write_flash \
--flash_freq 80m --flash_mode qio --flash_size 32m \
0x0000 "boot_v1.4(b1).bin" 0x1000 espruino_esp8266_user1.bin 0x37E000 blank.bin

*** Get esptool.py from https://github.com/themadinventor/esptool

*** To flash a 4MB esp8266 (e.g. esp-12) via wifi use (with appropriate hostname):
./scripts/wiflash espruino.local:88 espruino_esp8266_user1.bin >espruino_esp8266_user2.bin

When I load the firmware with the same command I was using before (which is just the same as in this README) by replacing boot_v1.4(b1).bin with boot_v1.5.bin, I can only see random(?) hex flow in the serial console:

f2nn\0x9elnn\0x9c\0xe2\0xec\0x0cb\0x1cp\0x0clb\0x0elrlp\0xf2n\0xe0\0x10\0x02\0x0c\0x0c\0x82\0x0cl\0x0c\0x0c\0x0c\0x0c\0x0c\0x0cb\0x0cn\0xe2|\0x02l\0x0cl\0x8e\0x8eb\0x8c\0xf2nn\0xee\0x00l\0x8c\0x8el`\0x02\0x90\0x12\0x12nn\0x0cl`\0x02\0x0e\0x02nr\0x8e\0x92\0x92n\0x0c\0x0c\0xe2\0xecl`\0x02p\0xf2n\0xe0\0x10\0x02\0x0c\0x0cr\0x8c\0x9c\0x9c\0xe2\0xe0\0x0c\0x0c\0x0c\0x0cb\0x0cn\0xe2|\0x02\0xec\0x8e\0x8e\0x8eb\0x8c\0xf2nn\0xee\0x00\0x0c\0x0cl`\0x02\0x90\0x12\0x12nn\0x0cl`\0x02\0x0e\0x02nr\0x8e\0x92\0x92n\0x0c\0x0c\0x02\0x8cl`\0x02p\0xf2n\0xe0\0x10\0x02\0x0c\0x0cr\0x8c\0x9c\0x9c\0xe2\0xe0\0xecl\0x0c\0x0cb\0x0cn\0xe2|\0x02l\0x8er\0x8c\0x0cb\0x8c\0xf2nn\0xee\0x00\0x0c\0x0cl`\0x02\0x90\0x12\0x12nn\0x0cl`\0x02\0x0e\0x02nr\0x8e\0x92\0x92n\0x0c\0x0c\0xf2ll`\0x02\0x0er\0x92\0x92n\0x0c\0x0c\0xf2ll`\0x02rl\0x8c\0x8cn\0x9c\0x8c\0xf2nn\0x9e\0x8c\0x9e\0xe2\0x8cr\0x12nnn\0x8c\0x0cl\0x8cbrrl\0x00\0x0c\0xec\0x12\0x92l\0xec\0x12\0x92\0x92\0x82\0x02\0x0c\0x0c\0x0c\0x0c\0x0c\0x8c\0x0c\0x0c\0x0clll~rl\0x00\0x0c\0xec\0x12\0x92llln\0x9c\0xe2\0x00\0x0c\0x0c\0x0c\0x0c\0x0c\0x0c\0x8c\0x0cl\0x92ll\0x0el\0x00\0x0c\0xec\0x12\0x92l\0x8c\0x90n\0xe0\0x8e\0x02n\0xec\0x92n~\0x12\0x02\0x8c\0x8cll\0xe0\0x80b\0x0c\0xec\0x8cllpb\0x82\0x02br\0x82\0x8c\0xecl`nl\0x8ep\0x8c\0xecl`bl`\0x02l\0x92\0x92n\0x02\0x0c\0x9en\0x8c\0x92\0xe2nl\0x9e|\0x12b\0x12\0x0c\0x0c\0x02l\0x0c\0x0c\0x0cl`\0x02rl\0x8c\0xe2\0xf2\0x92p\0x02\0x82nn\0x80l\0x12ll\0x0c\0x0c\0x02l\0x8eb\0xec\0x8e\0x02\0x0c\0x0c\0xe2\0xe2\0x92`\0x02rl\0x00l\0x9c\0x9e|\0x00\0x8cl\0xe0|\0x02\0x0c\0x0c\0x0c\0x8c\0x0cl\0xe

Loading seems to success though:

Connecting...
Erasing flash...
Took 0.08s to erase flash block
Wrote 4096 bytes at 0x00000000 in 0.4 seconds (82.1 kbit/s)...
Erasing flash...
Took 1.68s to erase flash block
Wrote 478208 bytes at 0x00001000 in 46.4 seconds (82.5 kbit/s)...
Erasing flash...
Took 0.08s to erase flash block
Wrote 4096 bytes at 0x0037e000 in 0.4 seconds (85.5 kbit/s)...

Leaving...