I've been searching for a solution more than a week and going over dozens threads here on XDA without finding an answer for my problem.
i have o2uk m7ul with hboot 1.57, emmc 9001 running stock rooted 4.4.2, twpr recovery, tempered and unlocked by htcdev and im looking for a way to go stock so i can update my rom and fw
(bootloader) version: 0.5
(bootloader) version-bootloader: 1.57.0000
(bootloader) version-baseband: 4T.27.3218.14
(bootloader) version-cpld: None
(bootloader) version-microp: None
(bootloader) version-main: 18.104.22.168
(bootloader) version-misc: PVT SHIP S-ON
(bootloader) product: m7_ul
(bootloader) platform: HBOOT-8064
(bootloader) modelid: PN0710000
(bootloader) cidnum: O2___001
(bootloader) battery-status: good
(bootloader) battery-voltage: 3836mV
(bootloader) partition-layout: Generic
(bootloader) security: on
(bootloader) build-mode: SHIP
(bootloader) boot-mode: FASTBOOT
(bootloader) commitno-bootloader: dirty-1f512bb6
(bootloader) hbootpreupdate: 11
(bootloader) gencheckpt: 0
this is what i've tried so far, please tell me if im missing something
1. i cant s-off the device with firewater or similar due to my emmc, although i didnt tried yet flashing bulletproof or cm nightly kernels (reading users feedback it didn't helped with this specific emmc)
2. i can relock, unroot and try to OTA, but i need the original recovery which i can't find for my device, i found an old recovery but probably ota will fail.
3. i have identical stock device, but i can't pull the recovery from it due to the hboot 1.57 version.
4. i can flash 4.4.3 custom rom or even stock rom but it won't update my firmware - firmware flashing is impossible (s-on)
5. i have o2 ruu.exe for KK4.4 sense 5.5, is it safe to oem lock and run it from fastboot? or i'll brick my device? if it is safe to use the RUU, will updating from 4.4 to 4.4.2 and then to 4.4.3 with OTA possible?