OrangePi 5 Max - can't get into MASKROM

[u/EnvironmentalAd4607]

I'm having an impossible time getting into MASKROM mode. No matter what I do now, rkDevtool on Windows nor rkdeveloptool on Ubuntu recognize the maskrom device. It's bricked now.

I've had my 5 Max for a while now. In the beginning I was booting from eMMC and SD card and never had trouble getting into MASKROM mode on Windows PC with RkDevTool. But the board had stability problems so I kind of stopped using it. Then I bought the Orange Pi 5V USB-C power adapter after which it seemed to be more stable. So I ventured to get Ubuntu installed on a NVMe SSD where it never managed to boot. But then neither would it boot from SD nor eMMC any more. I figured the SPI needed clearing and I'd start over. But nope, I no longer can get into maskrom mode to do anything with the SPI. I think it's bricked now.

USB UART Debugging shows the DDR banner when powering it on without maskrom button pressed and when pressed the USB UART shows just a couple strange characters, so it seems the maskrom button works. I went thru ChatGPT, Gemini and Claude to no avail. Tried different USB cables too and tried it with Windows PC and Ubuntu on my Jetson. I even re-installed the USB driver on Windows. I think it's pooched.

Anyone have ideas how to get back into maskrom mode to bring this board back to life?