How do I run from SD card (not flash the onboard flash)

[cellularmitosis]

Hi,

Every time I try to boot from the SD Card, the blue LED lights up and the CI20 copies the SD Card to the onboard flash.

This isn't what I want -- I want to boot and run Linux from the SD Card.

Am I missing something obvious? Do I need to install a custom bootloader onto the SD Card?

[latinovic]

Hi,
In order to have CI20 booting from SD card you should do following:

Build u-boot from source as instructed here:

https://www.elinux.org/CI20_Dev_Zone

Download RFS from one of following locations:

http://mipscreator.mips.com/CI20/images/default_NAND/Debian8_20160602/rootfs_2016_06_02.tar
http://mipscreator.mips.com/CI20/images/default_NAND/Debian8_20150909/rootfs_2015_09_09.tar

Burn u-boot to SD card

• Determine the device name of the SD card:
  run lsblk command before sd card is inserted, run lsblk command after sd card is inserted, see the difference.
  /dev/sdd is used in my case.
• Unmount sd card

sudo umount $SD_MOUNT_PATH

• Burn uboot

sudo sfdisk /dev/sdd -uS -L << EOF
4096,,L
EOF
sudo mkfs.ext4 /dev/sdd1
sudo dd if=/dev/zero of=/dev/sdd bs=1K seek=526 count=32
sudo dd if=./CI20_u-boot/spl/u-boot-spl.bin of=/dev/sdd obs=512 seek=1
sudo dd if=./CI20_u-boot/u-boot.img of=/dev/sdd obs=1K seek=14
sync

Unpack RFS to SD card

mount SD card (/dev/sdd1)

sudo tar -xzpf ./rootfs_2016_06_02.tar -C $SD_MOUNT_PATH
sudo sync

Boot CI20

• Insert SD card
• Make sure that JP3 is set to boot from SD card (2,3)
• Power on the board