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[CRITICAL] Device stuck in Bootloader Mode (PID 5A16) after sending undocumented 0x77 command #12

Description

@1v14RK05

Description: While experimenting with the scripts, I accidentally sent an undocumented byte 0x77 (without parameters) to my UT61E+. Immediately after this, the multimeter entered a recovery/bootloader state and has not returned to normal operation since.

Device Status:

Model: UNI-T UT61E+

Current USB ID: VID_F517 & PID_5A16 (instead of the normal HID ID).

Screen: ON

Behavior: The device is recognized by the PC as a "USB Input Device" (HID), but it no longer sends measurement data. The official UNI-T 2.0 software recognizes it but is extremely slow and fails to read data correctly.

What I have tried:

Full power cycle (removing batteries for 10+ minutes).

Monitoring traffic with Wireshark: I see GET_DESCRIPTOR requests and some URB_INTERRUPT traffic, but no valid measurement packets.

The device identifies itself with Firmware Revision 37.01 and Protocol 1.10 while in this state.

Request: Does anyone know the specific HID command (8-byte sequence) to force the microcontroller to exit the bootloader mode and jump back to the User Application? Or perhaps a "Reset" command that could clear the bootloader flag in the EEPROM?

Any help to "unbrick" the unit via software would be greatly appreciated.

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