https://www.hovatek.com/forum/thread-11802.html

[Tutorial] How to revive dead Mediatek by soldering PCB mount points

notes

- this can help revive totally dead mtk device, does not charge nor power
- 3 ways this can happen:

1. bad preloader.bin
  - can bet corrupted on own, can be flashed wrong, or if “format” used in sp flash tool without reflash
- see recovery/reflash guide at 
https://www.hovatek.com/forum/thread-286.html

2. interrupting sp flash tool mid-flash
https://www.hovatek.com/forum/thread-286.html
- shaking usb cable, disconnection from impatience, or sp flash tool error mid-flash
- see revive guide at 
https://www.hovatek.com/forum/thread-808.html

3. flashing wrong variant
- happens commonly with tecno d5 and infiinx not 2 x600
- phone goes totally dead after flashing incompatible firmware
- fixes for 1 and 2 do not work

- Properly try fixes for 1 and 2 before considering scenario 3 as you could damage your phone for good doing this.
- You’ll need to join 2 points on the phone’s motherboard then connect the phone to PC via USb cord for flashing.

I’ll be visiting the links for 1 and 2, then returning here for the mount point soldering guide for 3.

1. [Tutorial] How to revive a totally dead Mediatek device
- power button has no effect
causes & solutions
A. Drained battery:
- reseat battery or keep charging
B. Interrupted flashing
- interruption of any flash tool can brick device
- device stuck in flash mode
- cord shaken, or error appears mid-task
- see 
https://www.hovatek.com/forum/thread-808.html (same as 2 above, will do below)
C. Flashing a wrong firmware
- most common cause, firmware that looks compatible may not be
-  check variants and build numbers! 
- download the right firmware and reflash
- hovatek can provide stock roms 
D. Flashing unsigned files / backed up firmware
- because of Secure Boot, a device can brick if an unsigned file or a backup from a different device of the same model is flashed
- flash factory signed firmware
E. Dead boot
- if the PC won’t even see the serial port of the phone, you’ll have to solder motherboard points to force this

2. [Tutorial] How to fix MTK or SPD bricked after interrupting flash or backup
- applies to both mediatek and spreadtrum/unisoc
- won’t power up or respond to buttons, but there is activity when connected to PC
- from interrupted flashing, cable or error
- can occasionally happen after correct flashing
- don’t interrupt flashing!
- maybe with “USB device nit recognized” error
Try:
- leave phone to charge for some time
- might take hours to even days but once phone is revived battery could read as low as 1%, leave it to keep charging, do not power up
tips to do faster:
A. reseat battery, then try powering (fastes)
B. hold power + vol up until it boots
C. remove battery, connect to charger without battery, insert battery while charging, then press power
D. you could keep pressing vol up + power during charging
E. if battery is inbuilt battery, hold down power, then connect to power source, and wait for phone to come up
F. remove batteru and charge with external charger then resume internal charging
G. uninstalk and reinstall usb drivers for chipset
One of the comments says “waiting for battery discharge”, i think this applies to devices without removable battery.
Trick: found third pin on usb port was “oosing power”. cut a usb cable and attached two (too many could overcurrent the curcuit) small leds between green and black wires to drain power withut removable battery
be sure to use emmc_user and not eboot when backing preloader to avoid brick. there is preloader.bin in emmc_user!

now back to the soldering guide
- to recover from flashing wrong variant you’ll need to join 2 motherboard points then reconnect to pc

How to join motherboard gold / mount points on a Mediatek Android device

https://youtu.be/jPn4FBAHib0
- 
- open phone to access motherboard. video says to unscrew it and to use precision tools.
- find golden pads labeled GND and KCOLO . in the example KCOLO is nowhere near GND. in the video some kind of foil tape was hiding KCOLO. [could look for KCOLO on FCC photos before opening phone]
- solder a thin wire to bridge from KCOLO to GND. in the video they placed an end of the wire first, then soldered. if you have palsy-like experiences like me, i might remind to stay very relaxed and calm, and practice it in really small steps one at a time, and find ways to brace hands so that shaking or jerking doesn’t reach the work.
- now just test with USB that the device shows to computer again. it should!
- disconnect and use sp flash tool to flash the right firmware
- when reimaged, remove wire

:D

i took the phone to a couple mainstream repair shops and they just said “sorry i don’t know what to do” also [parts supplier databases had no entries for the device and they had not heard of manufacturer. in future could/might be helpful to find phone with manufacturer that repair shops relationship with]
so is exciting to find repair guide !!