Can't use SD card and run "run install_linux_fw_sd" command

Embedded Devices Linux
, , ,
1

Hi,

I am trying to boot from an SD card as mentioned in the getting started process where I insert a Fat formatted SD card then stop the autoboot and run the following command: “run install_linux_fw_sd”.

I was able to achieve this process on the connectcore 8m nano dev kit, but trying to use the same process on a customized board with the same cc8mn processor and all other related things, I was able to perform the serial connection and see the default uboot the same ay with the dev kit.

When I try to run the same command to boot using the SD card files: “run install_linux_fw_sd”, i get this message: “unable to select mode”, I verify that the SD card is working by doing the process on the dev kit, and verified that the connection from the SDcard holder to the board are correct because removing the card would make the message no SDcard inserted. So it is detecting it but not able to initilize or read it for some reasons.

Any ideas or suggestions that would help?

Thank you!

image
image683×433 7.05 KB

2

The “mmc dev 1 unable to select mode” error in U-Boot usually means the system can’t initialize or communicate with the SD card (MMC device 1) due to a timeout, often because the

correct speed mode (like UHS SDR25) isn’t enabled or set, or there’s a hardware/device tree issue preventing voltage selection. To fix this, try setting a specific speed mode with mmc part dev 1 mode <speed_mode_number> (e.g., mode 6 for SDR25), ensure CONFIG_MMC_SPEED_MODE_SET is enabled in U-Boot, and check your board’s device tree for proper SD card configuration