I tried using the factory image as an upgrade image, and LuCI rejected it as "The uploaded image file does not contain a supported format. Make sure that you choose the generic image format for your platform."
Are there some special instructions to follow for that case?
Have you tried using sysupgrade, yet? Upload the image to the router's /tmp, then do a sysupgrade -n 'image'. You'll be reconfiguring it from scratch, of course..
... but I'm not sure which to write to. I tried writing to "firmware" and I think I narrowly escaped bricking the router, because it overwrote some sort of settings partition and the router rebooted with some FS read error messages in dmesg and reset its configuration.
Do you have any idea which partition I should write that image to?
I realized I missed a direction on the e3000 wiki page, you are supposed to convert the squashfs.bin into a "trx" by running e.g. nathan@debian:~/t$ dd of=firmware.trx bs=32 skip=1 if=lede-17.01.2-brcm47xx-generic-linksys-e3000-v1-squashfs.bin 123008+0 records in 123008+0 records out 3936256 bytes (3.9 MB, 3.8 MiB) copied, 0.194182 s, 20.3 MB/s nathan@debian:~/t$ scp firmware.trx root@192.168.1.1:/tmp/
... then you can run sysupgrade firmware.trx, and it will upgrade.
And that got me to 17.0.2. If I'm feeling adventurous I might even try upgrading to 18.xx
sysupgrade is supposed to take *.bin files as well, but there was a bug breaking this automated header stripping that only got fixed ~half a year(?) ago, it should work again from 18.06.0 upwards.
I tried dd'ing the 'snapshot install image' from the file matrix (nathan@debian:~/Downloads$ md5sum firmware.trx acc041e55c3bbaf615fa424b1c98b282 firmware.trx nathan@debian:~/Downloads$ md5sum openwrt-brcm47xx-generic-linksys-e3000-v1-squashfs.bin abdb46931f1292a5540aa75e78f19274 openwrt-brcm47xx-generic-linksys-e3000-v1-squashfs.bin)
And while that installed Luci no longer worked.
I then tried installing the "open wrt install image" nathan@debian:~/Downloads$ md5sum openwrt-brcm47xx-generic-linksys-e3000-v1-squashfs.bin firmware.trx abdb46931f1292a5540aa75e78f19274 openwrt-brcm47xx-generic-linksys-e3000-v1-squashfs.bin b754e8d676044330b8d20bf257cd7f18 firmware.trx and that also installed overtop the previous install and Luci came up after reboot. I'm not sure which one I should have used, so hopefully this final note helps someone else.