Remove Ubuntu files from MV1000 Brume

I have installed Ubuntu on the MV1000. I switched back to OpenWRT by using the “switch_system openwrt” command. I would like to remove the Ubuntu files from the device. Can I just delete these files or is there some procedure that needs to eb followed. I don’t want to be stuck with a device that won’t boot up. Thanks.

You can delete Ubuntu files directly.
On the openwrt,do the following:

rm /data/* -rf;sync

The Ubuntu files will be removed.