- As soon as you read that press enter, type root and than press enter again (just do it, don't care about the logs scrolling).
- Most likely the router is still printing the boot log, leave it boot until it stops.
- If everything went ok you should have full root access "root@EX5601-T0:/#".
The original method in the commit message may not work any more due to Zyxel / ISP firmware updates. A different flashing method using a custom uboot is described in the topic linked below around post 300. This does require you to open the device and use a serial connection. It also does not allow you to easily go back to stock Zyxel firmware since it changes the storage layout. I've converted multiple EX5601s with the custom uboot method and it always worked.
Yes this install method is not guaranteed to work any more due to zyxel firmware updates however the alternative install method with the custom uboot will work since it bypasses the installed firmware completely.