Yes, I did so, but this grub problem has been solved by updating to entropy rc_25.
BUT TODAY THE OLD PROBLEM RETURNED - updating to rc_26 is not possible,
and the system base backed up yesterday has vanished

).
Seems I need help once more.
Rainer
I tried to solve the problem by using emerge & Co. without success.
Here come some error messages:
>> :: (41/41) >>> 2 Pakete
>> ## Paketprüfsumme stimmt überein: app-shells:bash-completion-1.3~0.tbz2
>> ## Paketprüfsumme stimmt überein: app-shells:gentoo-bashcomp-20101217~0.tbz2
>> ++ (1/122) >>> sys-kernel/linux-headers-2.6.38
>> ## Entpacke Paket: sys-kernel:linux-headers-2.6.38~0.tbz2
>> ## SPM: Vorinstallations-Phase
Traceback (most recent call last):
File "/usr/lib/entropy/libraries/entropy/spm/plugins/interfaces/portage_plugin/__init__.py", line 2062, in _pkg_setup
licenses = package_metadata.get('accept_license'))
File "/usr/lib/entropy/libraries/entropy/spm/plugins/interfaces/portage_plugin/__init__.py", line 1797, in _portage_doebuild
mysettings = self._get_portage_config(os.path.sep, root)
File "/usr/lib/entropy/libraries/entropy/spm/plugins/interfaces/portage_plugin/__init__.py", line 3556, in _get_portage_config
raise SPMError("SPMError: %s" % (repr(e),))
SPMError: SPMError: ParseError()
>> ## QA: Kann Schalter des QuellPaketmanagers nicht ausführen für sys-kernel/linux-headers-2.6.38.
>> ## Bitte dies melden. Hänge dies an: /var/log/entropy/entropy.log [setup]
>> ## Installiere Paket: sys-kernel/linux-headers-2.6.38
>> ## [Linux system headers]
>> ## Aktualisiere Datenbank: sys-kernel/linux-headers-2.6.38
>> * cannot execute handlePackage on this repository. Kann nicht weiterarbeiten.
amd64 rainer # emerge --sync
[Errno 2] No such file or directory: '/var/lib/layman/make.conf' in /etc/make.conf
amd64 rainer # layman -a sabayon
* Program "/usr/bin/git" not found
* Failed to add overlay "sabayon".
* Error was: Adding overlay "sabayon" failed!
Rainer