Writing option bytes on STM32 G070/G071/G081

[spark-ict]

when i try to make the flash writable again rith rt-flas i get an error, looks like option boot writting is not implemented yet for this chip

• Programmer/board type: STlink V2
• Operating system an version: Linux
• stlink tools version 1.7.0
• stlink commandline tool name: st-flash
• Target chip (and board, if applicable): STM32G070/G071/G081

command:  sudo ./st-flash --area=option_boot_add write 0xdffbe1aa

Commandline output:

2021-06-22T16:37:45 INFO common.c: G070/G071/G081: 36 KiB SRAM, 128 KiB flash in at least 2 KiB pages.
2021-06-22T16:37:45 ERROR common.c: Option bytes boot address writing is currently not implemented for connected chip
2021-06-22T16:37:45 ERROR common.c: Flash option write failed!

thank you for helping us. if you want us to do further investigation please let me know

best regards,
Guus Hamann
Rural Spark

[Nightwalker-87]

The required device-specific parametres according to the related ST reference manual are available in the chip file and have been verified with #1216. However they don't appear to be read due to a missing implementation in option_bytes.c.

[Nightwalker-87]

@gszy @simplerobot: I looked at the switch-case in int stlink_write_option_bytes(stlink_t *sl, stm32_addr_t addr, uint8_t *base, uint32_t len) within option_bytes.c
There we find: case STM32_FLASH_TYPE_G0: without any break, so in this case it should proceed with case STM32_FLASH_TYPE_G4: where stlink_write_option_bytes_gx(sl, addr, base, len) is called, so it should actually work...

[Nightwalker-87]

I've done some further research on this issue:
The only evidence for the observed behaviour is found in option_bytes.c (Line 1078):

  switch (sl->flash_type) {
  case STM32_FLASH_TYPE_F7:
    ret = stlink_write_option_bytes_boot_add_f7(sl, option_bytes_boot_add);
    break;
  default:
    ELOG("Option bytes boot address writing is currently not implemented for connected chip\n");
    break;

This implies that a wrong flash_type must have been defined in the respective chip file G070/G071/G081 in the particular case (flash_type = 5 -> F7 instead of flash_type = 7 -> G0), dependent on the order of the defined enum stlink_flash_type { } in stlink.h

Commit 8d96e76 introduced a human readable form for the parametre flash_type to avoid such bugs and/or accidental mistakes.