[Q] Stuck in boot loop, can only access Fastboot?

I previously unlocked my HTC One, changed the CID and MID and installed an official GPE Edition ROM. Everything worked fine. I retired it and sent it to a friend who had a company attempt to "unlock" it. Apparently all they did was revert my S-OFF and then change the CID and MID back to AT&T defaults. Now the phone is stuck in a reboot loop - it boots up, asks what language you want, then immediately reboots.

I have verified the CID and MID are correct for AT&T, but the stock EXE RUU fails and so does attempting to push a ZIP RUU. I've also tried a Guru Reset ROM, but it fails as well. If I try to SuperCID, that also fails so I cannot even reload stock Android. The HBOOT screen reports unlocked and tampered.

Here is the fastboot output:

(bootloader) version: 0.5
(bootloader) version-bootloader: 1.54.0000
(bootloader) version-baseband: 4T.21.3218.21
(bootloader) version-cpld: None
(bootloader) version-microp: None
(bootloader) version-main:
(bootloader) version-misc: PVT SHIP S-ON
(bootloader) serialno: (removed)
(bootloader) imei: (removed)
(bootloader) meid: 00000000000000
(bootloader) product: m7_ul
(bootloader) platform: HBOOT-8064
(bootloader) modelid: PN0712000
(bootloader) cidnum: CWS__001
(bootloader) battery-status: good
(bootloader) battery-voltage: 4051mV
(bootloader) partition-layout: Generic
(bootloader) security: on
(bootloader) build-mode: SHIP
(bootloader) boot-mode: FASTBOOT
(bootloader) commitno-bootloader: dirty-5d4c562c
(bootloader) hbootpreupdate: 11
(bootloader) gencheckpt: 0


Any suggestions for how to get started returning this to stock? I'm at a complete loss here.

This morning I attempted to flash both CWM and TWRP recoveries, both flash successfully but I cannot boot into them. When I choose recovery it goes straight back into the normal GPE ROM and asks for my language, then reboots.

Any help before I just throw this thing in the trash?

BenPope said:

fastboot erase cache
That will allow you to get into recovery.

Click to expand...

Click to collapse

That did it and I was able to get into CWM (non-touch). Attempting to sideload an AT&T RUU now. Thanks.

I am still unable to get an official AT&T or GPE ROM to install, but I was able to get Cyanogenmod 10.2 to install and actually boot into the UI. Rumrunner won't S-OFF though. Is it possible to restore to stock AT&T from Cyanogenmod with S-ON?

Thanks, TWRP and the AT&T 4.3 ROM worked. I still cannot S-OFF, but I was able to enter the SIM Unlock code and it worked, so I'm in a much, much better spot than before. SIM unlocking was the whole reason I needed to get a stock AT&T ROM back on here. The underlying OS is still the GPE ROM however, but I think I'm okay with that. Probably need S-OFF to fully restore to AT&T.