dual-booting.md

Dual booting

This is only supported on images up to 0.5.x.

U-Boot provides the ability to select which OS image/kernel to use when booting.

The following instructions were borrowed from user maal on the PINE64 forum.

Note: This is experimental and may break upgradability.

1. Mount the boot partition

If it's not already mounted, make sure /boot/efi is mounted. The <device> should be sda6 if booted from USB, mmcblk0p6 or mmcblk1p6 if booted from microSD.

mount -t vfat /dev/<device> /boot/efi

2. Edit extlinux.conf

Add the following entries to /boot/efi/extlinux/extlinux.conf:

timeout 1200
default kernel-4.15
menu title ROCK64 Boot Menu

Also, make sure you copy and modify the label/kernel/initrd/fdt/append lines for additional boot options.

The final /boot/efi/extlinux/extlinux.conf file should look like similar to this:

timeout 1200
default kernel-4.15
menu title ROCK64 Boot Menu

label kernel-4.4
    kernel /Image
    initrd /initrd.img
    fdt /dtb
    append earlycon=uart8250,mmio32,0xff130000 rw root=LABEL=linux-root rootwait rootfstype=ext4 init=/sbin/init coherent_pool=1M ethaddr=${ethaddr} eth1addr=${eth1addr} serial=${serial#} rock64_label=kernel-4.4

label kernel-4.15
    kernel /Image-4.15
    initrd /initrd-4.15.img
    fdt /dtb-4.15
    append earlycon=uart8250,mmio32,0xff130000 rw root=LABEL=linux-root rootwait rootfstype=ext4 init=/sbin/init coherent_pool=1M ethaddr=${ethaddr} eth1addr=${eth1addr} serial=${serial#} rock64_label=kernel-4.15

This will default boot from the kernel-4.15 label after a 2 minute (1200 * 1/10s = 120 seconds) timeout. *(thanks to easyfab for the correction).

This might seem obvious, but make sure to copy your new kernel and OS files (ex: Image-4.15, initrd-4.15.img, dtb-4.15) to /boot/efi/.

3. Reboot

Unmount the boot partition, then reboot:

umount /dev/<device>
reboot

On reboot, you should be presented with a menu similar to this:

ROCK64 Boot Menu
1:      kernel-4.4
2:      kernel-4.15
Enter choice:

Enter your choice, and it should boot the desired image/kernel.

Enter choice: 2
2:      kernel-4.15
Retrieving file: /Image-4.15
...