[Redmi K20 Pro / Xiaomi Mi 9T Pro ROMs, Kernels, Re] UltimateByte:
Hello,

Thanks for the work. First time flashing a Xiaomi phone from stock. trying to make a second life for this unsupported phone. Would serve a family member well.

I have to give some feedback about instructions, I do believe it could use improvements. Information and download links are scattered all around and were messy to find and apply. Between Xiaomi's default locked bootloader, their own dead links, and instructions not provided in most ROMs topics, and every single link for every single recovery image or ROM being on a different platform... It feels like a mess to me, to follow all these scattered steps when you didn't flash a phone for years. Let alone newcomers. At least I've got some experience and know what adb and other things are, but it's certainly not friendly at all to newer users, as it currently is. I think it misses the occasion to get widely adopted by providing clearer instructions.

Anyway, I've successfully unlocked the bootloader, flashed the custom orange fox recovery, formated everything...

Now I'm stuck on something very simple preparing the rest of the procedure: How or where do I download Gapps? I don't see any download link at the provided URL https://t.me/vosraphael/26358

I used to use OpenGapps, but they moved to Sourceforge since the last time I checked and they stopped providing new versions since a year and a half, so... Wat do?!

EDIT: Used this for Gapps : https://mindthegapps.com/download/

Unsure if compatible but... That's a start.

Now I'm trying to figure out what is the procedure to flash ZIPs on a phone with no OS on it.

EDIT2 : Used adb sideload <file.zip> as admin and flashed the 3 zips, putting the phone into ADB mode after starting adb server (adb stop-server, connect phone, adb start-server, then enter ADB mode using "update" feature. Enabling ADB mode by the option menu seems to break everything and require phone reboot.

Overall, here are the commands in my case:

adb sideload fw_raphael_miui_RAPHAELGlobal_V12.5.2.0.RFKMIXM_edbf5f63e8_11.0.zip

adb sideload voltage-3.0-raphael-20231208-1419-OFFICIAL.zip

adb sideload NikGapps-basic-arm64-14-20231107-signed.zip

Not sure if working, I see the Voltage logo for now, that's a good start.

Hope it helps newcomers a bit.

EDIT3: After 35 minutes stuck on boot menu, I tried going back to recovery for another flash with other Gapps. But it only goes in fastboot. So seems bricked, so now gotta figure out how to go from here.

EDIT4: So the bottom point is my OrangeFox install was incomptete. I've recovered the phone using official image with MiFlash. Then unlocked the phone again. Then installed TWRP. Then formatted Data as it was encrypted. Then added back the ZIP files. Installed OrangeFox ZIP via TWRP. Within OrangeFox, wiped everything as needed, installed the 3 .zip files, and voilà, welcome screen for Voltage in less than a minute after reboot.

First look at the ROM, looks like it has some common points with GrapheneOS. I love how it shows current used permissions. Seems rock solid. Definitely was worth the trouble. Now to see if this could fit my family member who needed a new phone. :)