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BB3 (MCGU GF4) Firmware Flash Failure and Device Unresponsive

Posted: Tue Oct 28, 2025 22:35
by wookinom
Hello, I need help with a serious issue.
I’m using a BB3 (BlackBox Mk3) with a Gunfighter Mk3 base and MCG Ultimate GF4 grip. I tried updating to the latest firmware: _BlackBox_Mk3_Unified_v2_19_9 , but I kept getting the error message:
"Device signature not correct" – flash failed.
So I mistakenly selected another firmware from the folder: _BB_Mk2_GunFighter_MCG_Ultimate_Twist_v2_19_9 and flashed it
sc 2025-10-29 040458.png

After flashing, the software suddenly shut down, and both the BlackBox and grip lights turned off. The device seems completely dead.

Now, the only way I can get any response is by pressing the red button on the BlackBox while connecting the USB cable — this gives me a solid blue light.
20251029_041232.jpg_compressed.JPEG


However, the Gunfighter base and grip are not recognized at all. The device only shows up in Z-Bootloader mode, but when I try flashing the correct Mk3 firmware again, I still get the same error:
"Device signature not correct."

I’ve attached the OP1 file as well.
4B4B3732.zip
(9.96 KiB) Downloaded 337 times


Please help me recover the device.

Re: BB3 (MCGU GF4) Firmware Flash Failure and Device Unresponsive

Posted: Wed Oct 29, 2025 13:39
by fallout9
Resolved on Discord.