Installing OpenWRT on the Zyxel LTE5398-M904

[frollic]

@fyychs

Is that because this version is a snapshot build?

yes

@fyychs

Next, I tried flashing the stock firmware with sysupgrade -F, but no luck,

probably a bad idea then, also not documented as a way back to stock.

@fyychs

How can I correctly install OpenWrt with the Luci web interface on said Zyxel router?

use the images from https://firmware-selector.openwrt.org/?version=SNAPSHOT&target=ramips%2Fmt7621&id=zyxel_lte5398-m904, they include the luci package.

@fyychs

Is there something wrong with my router, because sysupgrade seems to do nothing at all?

probably not.

you could also try zycast from Method to flash any NR7101