OpenWrt support for Zyxel LTE5398-M904

[mkrle]

Something to try (at your own risk) if anyone is interested in dual boot:

Zyxel NR7101 low performance

You can simply write an OEM image to the "Kernel" partition using mtd. Or you can write it to the "Kernel2" partition and keep OpenWrt in "Kernel" if you like. Then you can switch to OEM from OpenWrt using fw_setenv BootingFlag 1 reboot and from OEM to OpenWrt using nvram setro uboot BootingFlag 0 nvram commit reboot