Yeah, it's like the bootloader writes bad information to the userdata partition if the recovery isn't stock. I haven't flashed a custom rom from the custom recovery, but I'm assuming the type your password issue would appear again. Yes, it's a combo of pure stock rom + custom recovery when this problem occurs. No, when I installed the 4.2.2 factory stock rom, I unzipped all the image files and typed these commands.
Code:
fastboot oem lock
fastboot oem unlock
fastboot flash bootloader <bootloader name>.img
fastboot flash boot <boot name>.img
fastboot flash system <system name>.img
fastboot flash userdata <userdata name>.img
fastboot reboot-bootloader
fastboot erase cache
fastboot reboot
I've also gone back and manually erased, formatted, and wrote the userdata partition again. Maybe I should try downgrading the bootloader to 4.2.1, reflash userdata, and flash the custom recovery?
Hmmm. Well, I can't say for sure, but I am willing to gamble that the bootloader relocates itself into a load-offset address so that it runs out of RAM rather than running directly out of Flash Memory. Much quicker that way. The implication of that is that once it is fully loaded into RAM and operational, you could actually erase the bootloader and suffer no ill effects - until you powered off the device. Then you would be in real trouble.
The point is, in the Google factory sequence, all of the partition flashing is done by the
new bootloader (4.18), whereas in your case none of it is done that way - except for the custom recovery flash. Here's the Google sequence:
- erase all partitions using currently installed bootloader (4.13)
- flash new bootloader and boot into it ( 4.13 -> 4.18 )
- flash all 4.2.2 ROM partitions using
new bootloader
whereas your sequence looks like:
- (no explicit erasures)
- flash partitions with old bootloader (4.13)
- reboot into new bootloader ( 4.13 -> 4.18 )
- erase cache
- flash recovery with new bootloader ( 4.18 )
very different!
Also, the "-w" switch used in the google sequence causes partition erasure and re-formatting (depending on partition type) prior to each partition's flashing.
Without going through the lock/unlock procedure, I suppose it would be possible to reflash all the partitions with 4.18 to see if the problem disappears. But, now that I said that, I realize my tab - which had an OTA upgrade - is sort of similar in that the partitions & files patched by the OTA were all initially flashed by 4.13 (by me), patched by the OTA, and then finally I flashed only the custom recovery with the 4.18 bootloader.
Doing further experimentation might mean attempting a bootloader rollback flash. I can't say that I've seen reports here of anybody trying it. And I can't say I blame them - there could be dragons hiding in that process.