I bought a pair of used CM4s, and both seem to have a booting issue (presumably from the eMMC)
Steps to reproduce:
- I used the CM4 IO board to connect the CM4 via USB from my macOS laptop.
- Next, I used the
usbbootrepo, and the instructions in the official guide to flash and update the firmware and install the Raspberry Pi OS (tried both 32 and 64 bit).
- Note that I fit the jumper on nRPI_BOOT as mentioned while flashing.
- The green activity light blinks rapidly for the above steps, indicating everything to be "seemingly" normal.
- As expected, Flashing the firmware/bootloader gives me a green screen on a connected HDMI screen.
- Next, I power off the board, remove the USB connection, remove the jumper, and turn on the power as per the guide.
- Sadly, I do not see anything on the screen, and the green activity light doesn't come up.
As a different approach:
I also tried using
usbboot to connect the device as
msd in the GitHub repo instructions and then used the Raspberry PI OS GUI Imager / Installer to flash the OS to the eMMC. This process goes fine, but when I boot the CM4 after the flash, again no activity, nothing on the screen.
I think the eMMC is fine because I can add/remove files with macOS finder (file browser). The data persists between physical disconnections.
I can reproduce this on both my CM4s which are 4 GB RAM and 32 GB eMMC versions. I have also tried different carrier boards with the same results.
What should I do? Any help is much appreciated.