Yes i see it in the schematics now. You are right.
Usually with rk3588 boards You connect the usb-c port with a usb - usb-c cable to the laptop usb-a port and flash it in maskrom mode.
My mistake was not to fully study the schematics. In the schematics i see the OTG port is wired to a USB 3 A port.
I had connected the usb-c to my computer with usb-c to usb A cable and did feed separately 12V to DCIN.
12V DC in is directly wired to the USB-C port pins. no reverse protection on the usb-c port.
I added now a diode similar to the DCIN diode. now can never happen again.
See attached image. this my change for future proof.Bildschirmfoto vom 2024-12-06 00-01-38.png
I will prepare a updated documentation and send it to You george in a private message so You can update the wiki page and the getting started page.