Caannot upgrade pi-star (two in fact)

[DG6DXG]

Hi all
On both I see :

Starting upgrade, please wait...
Detected Pi-Star 4.1.4-RMB running on RPi hardware, attached to stm32dvm modem...
Something went very wrong, I cant tell what version I am running
Sleeping a few seconds before making the disk Read-Only...
mount: /: mount point is busy.
Finished

[MW0MWZ]

Also the "RMB" version isn't my work, please ask the author for support.