WARNING:VERY RISKY, TRY EVERY OTHER KNOWN UNBRICK METHOD FIRST!!! ONLY DO THIS AS A LAST RESORT!!!
ALSO THIS IS AT YOUR OWN RISK, I WILL NOT TAKE ANY RESPONSIBILITY FOR DEVICES DAMAGED IN THIS PROCESS!!!
Recently I flashed a wrong/corrupt bootloader resulting in the (probably) worst kind of brick achievable without doing physical damage to the device resulting in a state where it won't boot into android, won't boot into recovery, cannot get into flashmode (vol+ while connecting to PC) and will not be recognized by a PC in any way. The only thing that worked was the green led, indicating that it was recieving power from some source.
Without a working bootloader, any kind of standard recovery method didn't have any effect.
As a last resort I disassembled my XD in hope to find a way to get it into MASKROM mode. To be honest I hadn't much hope for this to work but it actually did
but it requires stripping the GPD XD down to the bare PCB including removing the Heatsink/RF-Shield covering the SoC and shorting out two pins on the board.
To do this you'll need:
-A small electronics screwdriver set.
-some plastic tool for prying the gpd open ( a guitar-pick would do)
-(Optional) A soldering-iron and some solder if you break something while disassembling.
- A microUSB cable
- (for now at least) a Windows PC
- RockChip Driver Assistant
- GPD Stock 3.4.9 Rom
(Any working rom will work but this is what I used to be save)
(Links provided by sectioneight.com by courtesy of PsyOps)
Follow this teardown thread https://boards.dingoonity.org/gpd-android-devices/teardown-of-gpd-xd-system-(blue-32gb)-and-my-thoughts/
until you're looking at this:https://imgur.com/a/IVcNJ
Be careful doing this, especially with the ribbon cables as they are very fragile and extremely hard to replace.
Unfortunately the NAND we're looking for is under the Heatsink/shield, fortunately it is actually not soldered to the board but only held in place by tiny little metal clamps. Take your trusty prying tool and carefully pry up the clamps and the thing on top (probably a heat-sensor of some sort) Be Careful not to break them:https://imgur.com/a/b8j8p
After that you should be able to see the SoC including the CPU, the GPU, some RAM and the NAND:https://imgur.com/a/0V9Cj
The NAND is the Chip in the lower right corner. It is the one with the white lining around it but as you can see it doesn't have any pins to short out. But with some trial and error we found out that you can get the device into MASKROM mode by shorting these two contacts on the board:https://imgur.com/a/ZCebs
Make sure to short the right ones because we couldn't figure out what the other ones do to the system.
Ok now to the execution of the recovery:
Start up batchtool and select your firmware IMG.
Plug the battery into the XD board ( without it it will fail to go into MASKROM mode and just turn off)
if the LED is glowing green by this point hold the power button (or whats left of it) until it's off
Use something metallic like a screwdriver or a paperclip to short the two contacts.
Plug in the USB lead to the pc and keep shorting the contacts until your pc recognizes the Device (having a friend plug in the usb helps) then stop shorting the pins. Your device should now be recognized by batchtool as a MASKROM mode device.
Now just press upgrade and wait. After that your device LED should light up red, indicating that it is charging off the USB.
Unplug, Reassemble (easier said than done) and your done.https://imgur.com/a/DX5pl
Let it boot (takes a long time at first) and charge if the battery is drained.
Can't say yet if my device got any lasting damage from the whole shebang but at least it is booting again.
If this happens again I'm considering soldering a hardware-switch to the pins to short them without opening the device