Originally Posted by qtybest
Is it necessary to flash the origional mmcblk0p2 in order to make a successful update to 5.0.4?
I do not think that the update changes (or cares about) mmcblk0p2. The version with SSH does not have any changes except adding missing files, so should not be a problem.
It is possible that the previous update attempt failed because the partition and kernel did not match, but left the partition in an unstable condition. This latest failed update may have changed the kernel and/or main partition, so you should flash a new 5.0.0 kernel, and use "dd" to copy a new 5.0.0 main partition to /dev/mmcblk0p1. Then perhaps run a "factory_reset" script to erase any residual /var/local settings that might interfere with an update.
In my case, I was able to successfully update to 5.0.4 after flashing a fresh 5.0.0 kernel and using "dd" to copy the "forensic" 5.0.0 main partition image, so you should be able to do that too...