In-Circuit Programming of SPI NOR Flash

[tsys]

Hi,

I do not think there is any reason to use external hardware for flashing. The SPI flash can simply be written from within the OS (or even u-boot). By default (I think even on the stock Debian?) the whole flash is exposed via

Code:

/dev/mtd0

. You can simply (and safely) write to the flash using the

Code:

flashcp

command from

Code:

mtd-utils

by running

Code:

flashcp <filename> /dev/mtd0

.

Even if you need to recover from a defective bootloader written to the SPI flash, you can simply short pin 6 of the SPI flash to GND and boot. This will render the bootrom unable to read from the SPI flash and have it fall back to reading the bootloader from other boot media like the micro SD card or eMMC.

The procedures described above are a lot less risky than attaching an external SPI flasher and do not require any additional hardware.