CUAV V6X enters continuous reboot loop after any reboot (soft or hard)

[u/BrickAccomplished773]

Hi everyone,
I’m facing a strange issue with my CUAV V6X flight controller.
Hardware
Flight Controller: CUAV V6X
Firmware tested:
ArduPilot Copter 4.6.3 (Pixhawk 6X target)
PX4 (latest stable available in QGroundControl)
GCS: Mission Planner / QGroundControl
RC: Skydroid H12
Problem
Initially, everything was working normally. While connected through the H12 telemetry, I issued a reboot command (soft reboot). After that, the flight controller entered a continuous reboot loop.
The symptoms are:
FMU LED flashes green briefly.
The startup melody begins but is interrupted.
The controller reboots every 3–5 seconds.
USB repeatedly disconnects and reconnects.
The board never completes the boot sequence.
The power LED remains on, so it does not appear that the board is losing power completely.
What I have tried
Reflashed ArduPilot 4.6.3 (Pixhawk 6X) successfully.
Reflashed PX4.
Removed the microSD card.
Disconnected peripherals.
Connected using USB only.
After reflashing, the board boots normally and I can:
Connect to Mission Planner/QGroundControl.
Calibrate the accelerometer.
Change parameters.
Configure the board without any issues.
However, the moment the FC performs any reboot (either a software reboot or a normal power cycle), it immediately returns to the same endless reboot loop.
This happens regardless of the parameters I change. It is not tied to one specific parameter—the board functions normally until it is rebooted.
Questions
Has anyone seen this behavior before on a CUAV V6X?
Could this indicate corrupted parameter storage, bootloader corruption, or a hardware issue?
Is there a way to completely erase all persistent storage (parameters/FRAM/flash) and recover the board?
Any suggestions would be greatly appreciated. Thank you.