GUIDE - Downgrade for HTC U11 (from Oreo to Nougat with S-ON) - Solution for var...

The purpose of this guide is to restore the phone in emergency cases and not only but also to perform a downgrade without the need to be in S_OFF (the utility of Sunshine, except in special cases such as the change of MID and CID which is indispensable, it comes much less!).

CAUTION
Do not do it if you do not have a clear vision of what you are doing: for inexperienced users it is a way to get a "paperweight", I do not accept any responsibility: you do it at your own risk!

This example refers to the European version of the Oreo firmware already in use: 2.33.401.10 NO BRAND(it can also be used with other versions)

ESSENTIAL REQUIREMENTS:
• HTC U11 smartphone NO BRAND version with Android Oreo vers, 2.xx.xxx.xx Dual Sim NO BRAND;
• Bootloader unlocked;
• TWRP Recovery installed;
• Status: S-ON (S-OFF as you know is not permanent).

MATERIALS REQUIRED:
• European version of the RUU Nougat 1.27.401.11;
• Minimal ADB / Fastboot;
• TWRP Recovery (latest version);
• TOOL Htc_Version_Tool.zip thanks @sabpprook for the great tool

PREPARATION FOR THE DOWNGRADE via PC WINDOWS 10 and earlier
• Download the RUU on your PC and rename it to 2PZCIMG (leave the .zip extension untouched) and copy it to
the external SD card of your mobile phone;
• Install on the PC Minimal ADB preferably renaming the destination in C: \ ADB for convenience;
• Download the TWRP and copy it into the c: \ ADB folder renaming it to twrp.img for convenience;
• Download HTC_Version_Tool and unzip it to a folder on your PC as you wish.

INSTALLATION FOR THE DOWNGRADE IN ANDROID NOUGAT
• Restart the phone in Download Mode (press the LOW VOLUME + POWER BUTTON simultaneously) and connect
it to the PC using the supplied original USB cable;
• Run the Minimal ADB and Fastboot program on your PC (a DOS window will open with the c: \ adb prompt) and
leave it open;
• If you have not yet updated the TWRP Recovery run this command otherwise go to the next step:
o fastboot flash recovery twrp.img
• Now you have to enter TWRP Recovery mode;
• Once entered, always with the phone left connected to the PC, type the command adb devices to check if our
cellphone has been recognized;
• Now run the HTC_Version_Tool program from the PC in the folder you previously unzipped and you will be asked to change the version number of your firmware: confirm with the ENTER key (if you have done something wrong just repeat the procedure).

• You have now finished and you just have to restart it in download mode like this:
run, from your PC, the Minimal ADB and Fastboot program and, at the prompt, type adb devices to make it recognize and then adb reboot download and all that remains is to start the RUU flash previously copied to the External SD card.

For now we do not have S-OFF, this can be useful for flashing the RUU to remove problems and repair the phone when there is not a current RUU running.

Good downgrade!

Great guide for downgrading, but you should credit me to the HTC_Version_Tool.

Shan12345 said:

Can you please help me with downgrading to Oreo from Pie. I have just update my u11 to ota released android 9 Pie. But it has lot of bugs. Now i need to go back to oreo. I have tried with your solution in this thread. But it didnt working. Can you please help?

Your case is same Problem with me

This solution still working for me.

But change cid from oreo to oreo work.

But downgrade from Pie to oreo you must add 1 step from @ziand

I several times downgrade from Pie to Oreo still working. Check this link

https://forum.xda-developers.com/u11/how-to/collection-htcu-u11-ruu-firmware-t3612048/post79616165

https://forum.xda-developers.com/u11/how-to/collection-htcu-u11-ruu-firmware-t3612048/post79617488

paulpier007 said:

Oppss... I messed up! For now, until proven otherwise, the operation is guaranteed only for those NO BRAND

@paulpier007
You didnt mess up pal! I`ve just done it on an EE branded HTC U11 - EVE__001

My problem was that because of the root procedure that i followed, OTA was not allowed. I had to use RUU to bring back to stock.
My phone had 1.13.91.3 but the only available RUU was 1.03.91.6. Every time I tried it I used to get the following error:

19 RU_MAIN_VER_FAIL os-version in android-info missing or i
19 RU_MAIN_VER_FAIL os-version in android-info missing or i
FAIL19 RU_MAIN_VER_FAIL os-version in android-info missing or i

so with the great help of your tool I managed to change the version and use the old RUU even though my phone is branded.

Many thanks pall maaaaany THANKS!

now i`m in the process of doing nandroid backups for each version so as we can add them to the "spreadshit"!

PS

I have tried the Unbranded RUUs as well but as expected Error 7 came in effect informing me that CID was saying "Hold your horses boy!"