[Notes] Flashing custom ROM on Redmi S2/Y2/YSL

CAUTION: DO NOT use a cellphone phone with a custom ROM for any banking purposes or if you plan to handle any sensitive data on your device — this includes OTPs that might get delivered in future. Don’t trust even the ROMs with ‘OFFICIAL’ title in them. (‘Official’ here practically doesn’t mean anything, so ignore any fancy title.)

Over the weekend, I spent significant time flashing a custom ROM on an old Redmi Y2/S2/YSL to repurpose this hardware. The MIUI is crap as it is, But, along with the bloatware it brought over in time, this device was practically end of life as it was. So I had to take the chance and try to revive it with a custom ROM.

Due to software incompatibility, what was supposed to be a 1-hour, or at the max 2-hour job, turned out to be a nightmare.

For anyone venturing to do this, below are the things that worked (and did not) for me!

I used Havoc-OS, Other ones I tried never flashed correctly or never booted (DotOS, Pixel Extended, LineageOS-unofficial, Elixir OS)

Havoc OS I downloaded: https://sourceforge.net/projects/havoc-os/files/ysl/

1. Use Mi unlock tool for enabling bootloader unlock. — https://en.miui.com/unlock/download_en.htmlNote: you will need a windows machine to run this tool! But straightforward. No glitches were seen.
2. Use Redfox recovery — https://orangefox.download/device/ysl
3. Ditch TWRP, It doesn’t work! (I followed this, and DID NOT work: https://forum.xda-developers.com/t/...cial-and-root-redmi-y2-s2-ysl.3854906/)Issues with TRWP — fastboot driver issues, which means ADB commands don’t work when inside TWRP (ADB sideload etc.)Together with weird storage encryption (Which I don’t remember enabling, doesn’t decrypt with any valid password that you remember setting on the device!)
4. Then the usual stuff: `adb reboot bootloader, `adb flash recovery redfoxrecovery.img`
5. Boot to recovery by: `Press VolumeUP + Power`
6. From menu — `adb sideload`
7. From computer — `adb sideload havoc-os-gapps.zip`

Finally, the OS booted. I installed some stuff. Everything that I tried is working till now.