I have to strongly disagree with you on this one. I rooted first phone,thought I had lost root. Ran factory reset from privacy menu. No custom recovery, and backup.
B.R.I.C.K.
If I would of had a custom recovery installed I could have gotten the phone straightened out(even without a backup)
Every thread I've ever read were someone who was rooted used the factory reset without having a custom recovery ended up with a phone that was totally useless.
I'll have to do some testing on this.
good info from experience is definitely worth listening to.
from looking at the kernel code, and hex editing lge init, and what zefie figured out about stock recovery and factory reset, it looked to me like all 3 of stock kernel, recovery, and init were required to handle a factory reset.
what i hadn't considered, that backs up your statement somewhat...
the custom su breaks some things.
like adb bugreport... it gives a whole slew of errors from su during a section of the bugreport.
it's quite possible that the factory reset process uses su at some point, and that at least could cause some problems if it is happening.
like i said, I'll have to check it out.
if using asadullah's tweaked stock rom, flash_image is in it, and adb is set to allow mounting r/w, so if I'm lucky i won't really brick something trying to verify.