First of all, thank you !
I spent all day trying to downgrade from oreo to nougat and you came to the rescue.
I didnt exactly follow your steps but the hosd part was what made it all work for me.
So make it clear and for anyone who's finding a difficulty in downgrading here are my steps:
-HTC Version Tool
-Unlocked phone with stock Oreo installed,twrp and unlocked bootloader
-Firmware zip (I got mine from here https://forum.xda-developers.com/htc...mware-t3387520
, download a full stock zip that corresponds to the SKU version you have and want to flash) > For example, my phone is PME UHL International 3.16.401
.2 Oreo so I chose PME UHL International 2.41.401.
-Stock Nougat RUU zip for your device. You need to search around for this one because there arent many sources for Nougat zips but mine was from here
1. Boot into TWRP then connect your phone to your pc then open adb terminal and run HTC Version Tool then change to the version of the RUU youre going to flash.
2.Reboot into download mode then run
fastboot getvar all
make sure that the (version-main) is the one you changed.
Then lock your bootloader with
fastboot oem lock
(This is to be able to flash the RUU)
3.Next, you have to flash the firmware zip so run
fastboot oem rebootRUU
fastboot flash zip YOUR_FIRMWARE.zip
(If it gives error that's ok)
4.Open firmware zip then extract hosd_signed.img to adb directory then run
fastboot flash hosd YOUR_HOSD.img
5.Reboot to RUUmode then flash firmware zip again
6.You need to put the RUU.zip you have in the sd card then rename it to "2PS6IMG.zip" ( Make sure its not 2PS6IMG.zip.zip) then reboot to download mode and choose to flash it (Vol up)
7.That should be it. If you boot into system and find youre stuck on HTC logo but somehow volume controls and power menu work then reboot to recovery and do a format then boot back into system then hold (Vol up + vol down+ power) for around 5 seconds until the setup screen displays. I don't know why this happens but it just does.
8.To restore IMEI and signal unlock bootloader,flash twrp then from recovery :
Originally Posted by sabpprook
[SIZE="3"]I found a post explain how to get IMEI back.
original post: http://bbs.gfan.com/android-9272781-1-1.html
Two methods for S-ON or S-OFF device, please do it under Nougat 7.0 firmware installed.
1. Reboot to TWRP recovery
2. Use the command below to erase persist partition
dd if=/dev/zero of=/dev/block/bootdevice/by-name/persist
Note: If you soft-brick your phone and lose recovery, system, bootloader unlock, then flash the same RUU zip as your version and android from external sd card through download mode. (It happened to me :/ )
I hope this helps you guys out. If I missed any step or something isnt well explained, please tell me.