I protracted it for a while but now it was definitely time: the upgrade of bananian to the latest version.
I protracted that, because although with 'bananian-update' there is a really nice upgrade script but on the corresponding website is said, that an SATA installation is not supported.
I then looked at the update scripts and after I found nothing that would affect my SATA installation, I gave that script a chance.
And what shall I say, it works fine. So you can pretty safely use the script 'bananian-update' for the sotware upgrade on your bananian-server.
For safety, I had not checked that the boot settings have not been overwritten and it boots back of the SATA drive.
For that use:
mount/dev/mmcblk0p1/mnt/ nano uEnv.txt
In this file, the boot parameter should still be root=/dev/sda1 .
Restart and that's it. If everything goes well and everything was still there, where it belongs !! ;-)