While trying to build custom roms for one of my cell phones, I managed to soft brick the phone. It was a Cat S42G, and I somehow managed to get it stuck in a preloader boot loop while attempting to change a stock kernel to have a TWRP recovery image. Fortunately for me (Praise God!) I was able to get it fixed with a tool called MTKclient.

https://github.com/bkerler/mtkclient

While this tool has some pretty good instructions, I just couldn't make it work on my Ubuntu distribution. It has several python dependencies that just don't seem to mesh up with my system. No matter what dependencies I installed or changed version of, I couldn't make it work.

Again, fortunately for me, the author also released a live DVD of Ubuntu with all of the proper dependencies installed. I burnt the live DVD to a thumbstick and booted it up in no time! Here's the link to that:

https://www.androidfilehost.com/?fid=15664248565197184488

My first attempt to fix the phone using the payload from the Android 12 OTA update zip didn't work at all, so I decided instead to clone my working CAT phone to the non-working one. That worked flawlessly, though it did take a long time to copy down the entire contents of the first phone, and then upload the files to the non-working phone.

The GUI worked really well on the MTKclient tool, and I am pretty impressed with the program overall. If you try it out, feel free to leave a comment with your results.

Linux - keep it simple.