TWRP OTG to load rom
I was using the d80010d_to_20c.zip firmware + SuperSu.zip + TWRP 188.8.131.52.zip.
i.e. "kitkat" with a custom recovery and root.
I had only the 3 above zips on the phone.
d80010d_to_20c.zip contains the kk_system and a custom kk_kernel, no bootloader.
The bootloader came from the LGFlashTool and a d80010d.tot file on my laptop.
After taking the April 8 OTA from AT&T, my phone was stuck in recovery.
Could not get into download mode or use ADB.
I made the mistake of wiping my phone hoping to get download mode to work.
I should have used the terminal in TWRP and typed:
dd if=/dev/zero of=/dev/block/platform/msm_sdcc.1/by-name/fota
which has been reported to work. After wiping the phone it was too late for this.
I was stuck in TWRP 184.108.40.206 which has OTG capability, so I loaded a usb flash drive with d800_Kitkat.zip,
connected it to my phone via an OTG cable, and copied d800_Kitkat.zip to the sdcard using TWRP.
Then flashed it using TWRP. I also flashed SuperSU.zip before booting to system. I'm back to stock Kitkat + root.
I'm hoping someone with Kitkat + root reports whether the April 8 AT&T OTA works on a rooted phone.
We know it fails badly on a custom recovery phone with Jellybean bootloader/custom Kitkat kernel/Kitkat system.
AT&T claims that it just updates Google+, Google Wallet, and makes Google Hangouts the default messaging app
which sounds safe but isn't.