This blog post describes my successful os re-install on a fairphone 2 which was giving "flash write failure" errors when flashing it with fastboot, with the flash_FP2_factory.sh script. I'm writing down my recovery steps for this in case they are useful for anyone else.

I believe that this is caused by the bootloader code which implements fastboot not having the ability to retry recoverable eMMC errors. It is still possible to write the eMMC from Linux which can retry these errors.

So we can recover by directly fastboot-ing a recovery.img and then flashing things over adb.

( See step by step instructions... )