Documentation for installing Ubiquiti Edgerouter-X has a bad link, and is confusing about which kernel to use.
Firstly, the link to an image from mega.nz is dead.
- v19.07.4 - openwrt-ramips-mt7621-ubnt-erx-initramfs-factory.tar 146e076754400c1fe377f917116ca299cfe37ffe4898f3f0330be067ed63da9e / sha256sum
Secondly, this paragraph is confusing.
Another clip is that at the moment the created firmware install images of section Firmware download cannot be used for this approach because they are too big in size. They are not fitting into the kernel partition (Device Flash Layout 3145728 vs. 3547875; the Ubiquiti installer is checking the filesize and fail; openwrt-19.07.4-ramips-mt7621-ubnt-erx-initramfs-kernel.bin; 08.11.2020). If you want to use them use the serial console and load the file via TFTP into RAM and install OpenWrt via sysupgrade after follow: Serial installation with TFTP for this.
The confusion (to me at least) is because of file naming in step 5;
Upload the kernel image to the device, access the device via SSH and install the firmware:
scp /path/to/your/kernel-image/openwrt-ramips-mt7621-ubnt-erx-initramfs-kernel.bin email@example.com:/tmp
The filename it says to SCP is the one the top section to only use when using Serial installation with TFTP, which has different instructions.
scp /path/to/your/kernel-image/openwrt-ramips-mt7621-ubnt-erx-initramfs-factory.tar firstname.lastname@example.org:/tmp
The difference in the filenames is one ends in 'factory.tar' the other 'kernel.bin'
The step after scp'ing the factory.tar/kernel.bin is to ssh to 192.168.1.1;
However the default user (and password) from the original firmware is ubnt, so i believe it should be
ssh email@example.com (and swap from eth0 to eth1)
Because the factory.tar is old, there are difficulties scp'ing the sysupgrade image across, i somehow stumbled across this combination of options to work with debian testing.
scp -O -o HostKeyAlgorithms=+ssh-rsa -o PubkeyAcceptedKeyTypes=+ssh-rsa openwrt-21.02.3-ramips-mt7621-ubnt_edgerouter-x-squashfs-sysupgrade.bin firstname.lastname@example.org:/tmp
Im having trouble recovering my 2 er-x after a power outage, so it could also be that im misinterpreting the above.