Can't install from SD card to EMMC on Odroid N2+

I have an N2+ which came preinstalled with CE a while back. The installation has gone through some updates up to CE20 20220921 but I am facing frequent freezes so I wanted to do a fresh install.

I have prepared an SD card in Rufus with the latest CE nightly v20 (20220921) and put it in the socket. Then I switched the SPI to Petitboot but when booting a few lines of errors flash by and then I am in the Petitboot menu options and CoreElec has not started or is available there. At the bottom of the screen there are some letters showing options for keypresses and the text

[mmcblk0p1] Processing new Disk device
Failed to launch petitboot, dropping to a shell

When pressing ENTER on the attached keyboard, it just generates the symbol “#”

What do I need to do?

OK, I’ve updated SPIBoot and then booted to the SD card via Petitboot. When I SSH into the box and run “installtoemmc” the script displays the message what it’s about to do but then nothing seems to happen. After a few seconds the network is just disconnected.

Do I need to format the EMMC or something?

Did you follow Wiki Option B? coreelec:odroid [CoreELEC Wiki]

Sure, otherwise “installtoemmc” would have triggered “No no no no don’t run from eemc…”
Maybe the script checks if CE is already installed on the EMMC and aborts?