[T-Mobile REVVL V+ 5G] gutclusters:
I wanted to create a thread about the REVVL 6 Pro phone I have to share things I learned to help the next person that comes along with the same issue I experienced. I've been in contavt with at least a half a dozen people with the same phone experiencing the same issue I was. Since I was able to solve it, I wanted to share.

PROBLEM​

My T-Mobile REVVL 6 Pro 5G started to randomly power itself off for no apparent reason. It would sometimes boot back up after several boot loops. Eventually, the phone would refuse to boot at all. It would boot loop forever. The phone will not charge. If you try to plug in the charger with the phone powered off, you will see a "Error! Please Plug Out Charger!" error screen.You might find the phone "crashes" in recovery or fastbootd.

CAUSE​

The phone is having issues reading the battery temperature. It reads that the battery is too hot and shuts down as a precaution. This is happening because the battery connector is failing, causing it to intermittently have issues reading the battery temperature. From what I can tell, this was a manufacturing defect in at least my phone.

HOW TO CONFIRM​

You can confirm this by looking at recovery logs in recovery and looking for ro.boot.bootreason on the second page, which will read kernel_panic after a failed boot attempt. Run "fastboot getvar all" in fastbootd mode (run fastboot in recovery instead of from initial boot) while connected to a USB port that can charge the phone and look to see if the battery-voltage line reads 0.

You may also find that the phone will charge and possibly boot if you apply a significant amount of pressure on the back of the phone. When looking at the back of the phone, go about an inch from the right and about 2 inches down and press in while the phone is on a flat surface. See below picture of location where you should press on the phone:

Revvl 6 5G

View attachment 6101635

REVVL 6 Pro 5G

View attachment 6101636

Maybe use the butt end of a screwdriver to press and try charging from powered off state. If the battery starts to charge, you've confirmed the issue.

This seems to be a manufacturer defect. The battery itself is in good condition, it's just the connector.

SOLUTIONS​

Fix 1: Replace the battery.

Fix 2: Find a tutorial on YouTube and follow it to disassemble the phone. When you get deep enough to access the battery connector, take a few tiny pieces of electrical tape and place them on top of the connector and reassemble the phone. The tape will act as a shim and apply pressure onto the connector when you torque the screws back in. This is the fix I went with.

Fix 3: If you have the necessary tools and are inclined to do so, maybe try reflowing the solder on the connector on the battery ribbon cable.

ADDENDUM​

The constant crashing may have possibly corrupted partitions on your phone. If this fixes the battery issue but the phone still fails to boot, you can find directions for re-flashing your phone to stock ROM. PLEASE REMEMBER TO BACK UP ALL THE CURRENT PARTITIONS ON YOUR PHONE BEFORE CHANGING ANYTHING! YOU'RE GOING TO NEED A FEW OF THESE PARTITIONS TO FIX THE IMEI AFTERWARDS!

About IMEI​

There are a lot of articles out there about restoring IMEI on various phones and none of them seemed to have worked for me. I fixed my IMEI by flashing nvcfg, protect1, and protect2 partitions from my initial backup to the phone. If you don't have a backup of these partitions, the steps at this XDA post should fix you up, but you'll need root.

Additional Stuffs​

Here is a MEGA link with various Magisk and TWRP boot images for the REVVL 6 Pro 5G. You will also find the preloader and copies of boot1 and boot2, which are the bootloaders and are stored in /dev/block/mmcblk0boot0 amd /dev/block/mmcblk0boot1 and be written via mtkclient with "mtk wf --preloader preloader.bin --parttype boot1" and "mtk wf --preloader preloader.bin --parttype boot2" switches if you've completely bricked your device to get it to boot again.