Thanks for the replies and suggestions. I solved it with an older Knoppix 3.2 I still had around (old versions se em no longer available on the net). Recreating grub however failed and was d one with the SL5 LiveCD.
It seems that newer distributions add the resize_inode and ext_attr featu res. If SELinux is enabled (probably the case on the LiveCD?) all written file s get the extended ACL entries. Maybe a LiveCD without SELinux and removing (with debugfs) the attributes could help but I didn't try that.
