Fallback rootfs uboot initramfs

[snowhite]

Hi. Using ArchLinux on the Odroid U3 I would love to have a conditional boot, basically two rootfs (primary on HDD) and if the HDD is not connected I’d like for it to boot the SD Card rootfs partition.

How can this be done? Do I need to tell u-boot to use initramfs?

[suriyan]

Hello SnowWhite,
This will help your situation. I am attaching all the files and steps relevant to your situation. This tgz has a README.txt which I am pasting here for reference.
- Suriyan
PS: I had updated a different thread, but realized that this post belongs here

$this->bbcode_second_pass_code('', 'This is for the below configuration:
Distro: Archlinuxarm
Requestor: SnowWhite
SDcard: Archlinuxarm
USB drive: Archlinuxarm

If USB drive has ArchLinuxArm, boot it (will only work if its /dev/sda1)
If USB drive not present then boot ArchLinuxArm in SD card.

Steps:
1. Install distro in SD card:
Will get /dev/mmcblk0p1 (VFAT) and /dev/mmcblk0p2 (rootfs)
2. Create 1st partition as ext4 in USB drive. Copy ArchlinuxARM rootfs in
the USB drive.
3. Edit /etc/fstab in both SD card and USB drive andn comment out /boot mount.
4. Copy boot.txt and boot.scr present in the boot directory to VFAT (mmcblk0p1)
partition of SD card.
5. Fuse new u-boot to SD card (by running ./sd_fusing.sh /dev/<SD card device>)
Example: ./sd_fusing.sh /dev/mmcblk0
6. Plug SD card in Odroid and power on.')