I’d backed up some files from a friend’s MacBook harddrive (onto an NTFS partition mounted in Ubuntu Linux). He then provided me with an external harddrive to copy them back onto. This wouldn’t work because many of the filenames weren’t supported by the FAT32 partition of the external HDD. This is the solution I chose.
gparted to resize the FAT32 partition on the external drive to a few hundred megabytes so I keep the software that was on there (probably not very useful).
Create a new partition in the free space, still using
gparted. This partition will need to be reformatted with MacOSX so it doesn’t matter what format you create. I first created an HFS+ partition with
gparted but it wasn’t recognised by MacOSX and although Ubuntu could mount it it wasn’t automagically mounted as external drives usually are.
This is solved by reformatting the partition as an unjournaled MacOS partition with MacOS via Applications -> Utilities -> Disk Utility.
Then both partitions (the resized FAT32 and the new unjournaled HFS+) should be mounted automatically in MacOSX and Linux systems. It is important for the filesystem to be unjournaled or Linux will mount it read-only.
To read MacOS partitions with Ubuntu you will need to install packages
hfsutils (maybe they are not all necessary).