Recently I got "my" Turris Omnia and it didn't take long to replace the original firmware with Debian.
If you want to reproduce, here is what you have to do:
Open the case of the Turris Omnia, connect the hacker pack (or an RS232-to-TTL adapter) to access the U-Boot prompt (see Turris Omnia: How to use the "Hacker pack"). Then download the installer and device tree:
# cd /srv/tftp # wget https://d-i.debian.org/daily-images/armhf/daily/netboot/vmlinuz # wget https://d-i.debian.org/daily-images/armhf/daily/netboot/initrd.gz # wget https://www.kleine-koenig.org/tmp/armada-385-turris-omnia.dtb
(The latter is not included yet in Debian, but I'm working on that.)
and after connecting the Turris Omnia's WAN to a dhcp managed network start it in U-Boot:
dhcp setenv serverip 192.168.1.17 tftpboot 0x01000000 vmlinuz tftpboot 0x02000000 armada-385-turris-omnia.dtb tftpboot 0x03000000 initrd.gz bootz 0x01000000 0x03000000:$filesize 0x02000000
192.168.1.17 being the IPv4 of the machine you have the tftp server
I suggest to use btrfs as rootfs because that works well with U-Boot. Before finishing the installation put the dtb in the rootfs as /boot/dtb.
To then boot into Debian do in U-Boot:
setenv mmcboot=btrload mmc 0 0x01000000 boot/vmlinuz\; btrload mmc 0 0x02000000 boot/dtb\; btrload mmc 0 0x03000000 boot/initrd.img\; bootz 0x01000000 0x03000000:$filesize 0x02000000 setenv bootargs console=ttyS0,115200 rootfstype=btrfs rootdelay=2 root=/dev/mmcblk0p1 rootflags=commit=5 rw saveenv boot
- rtc doesn't work (workaround:
mw 0xf10184a0 0xfd4d4cfain U-Boot)
- SFP and switch don't work, MAC addresses are random
- wifi fails to probe
If you have problems, don't hesitate to contact me.
Also check the Debian Wiki for further details.