Hello, I am experiencing an issue with a Here-4 GPS used with a Cube Orange Plus, connected via CAN. The unit was initially stuck in a solid white LED state. After recovering it using ST-Link and flashing the firmware, the GPS worked correctly and achieved a 3D fix. During the first few flashes, when the CAN interface was still working, I tried both updating the GPS firmware via ArduPilot and also leaving it without updating, but in both cases the unit still became corrupted again after a few power cycles. After several normal power cycles, the unit consistently degrades into a non-functional state.
After multiple power cycles, the LED turns solid white (bootloader / recovery state). Occasionally, the LED shows a pink or magenta slow “breathing” pattern. CAN and UART communication stop completely, and the behaviour becomes inconsistent between boots. The LED color and brightness also change depending on the power source, for example, when powered from ST-Link versus an external 5V supply.
The unit was initially recoverable via ST-Link and the firmware would run briefly after flashing. After further power cycles, the firmware no longer runs reliably. Eventually, the STM32CubeProgrammer connection became unreliable, and now the MCU connects intermittently and flash erase or programming fails, even with RDP set to Level 0 (AA), no security or write protection enabled, and a stable external 5V supply.
I have already tried a full chip erase, tested different BOR levels (default and higher), tested on multiple CAN ports, and powered the unit using an external 5V supply. The PCB was also cleaned with isopropyl alcohol. Despite these steps, the issue persists and has progressively worsened.
Currently, the unit no longer operates. CAN and UART are non-functional, flash erase and programming are unreliable or fail, and the LED indicates either bootloader mode or a magenta slow “breathing” pattern. Based on the behaviour and progression, I believe this is a hardware-level failure involving the MCU, flash, or power domain.
I would like to know whether this is a known failure mode for Here-4 units, whether this unit qualifies for repair or replacement, and if there are any additional diagnostic steps you would recommend.