I’d be happy to outline my steps.

$ sudo kpartx -av image_you_want_to_convert.img
add map loop0p1 (252:5): 0 117187 linear /dev/loop0 1
add map loop0p2 (252:6): 0 3493888 linear /dev/loop0 118784
$ sudo mount /dev/mapper/loop0p2 /mnt
$ sudo sed -i ‘s/^\/dev\/mmcblk/#/g’ /mnt/etc/fstab
$ sudo mksquashfs /mnt converted_image_for_berryboot.img -comp lzo -e lib/modules
$ sudo umount /mnt
$ sudo kpartx -d image_you_want_to_convert.img

These steps above are the steps that are on the berryboot wiki. I’ve done a lot wrong but I’ll stick the the major mistakes I made.

Firstly I tried to do this without enough virtual HDD space. I had the max HDD space of the virtual machine set too low. Secondly I made the mistake of not updating the kpartx and squashfs-tools. You can get these by inputting “apt-get install kpartx” and “sudo apt-get update && sudo apt-get install squashfs-tools” in your terminal.

Third thing I did wrong was input the wrong filepath for the .img that I tried to convert. The easiest way to do this was type “sudo kpartx -av” and then drag the file to the terminal. That will make sure the path is automatically added. For me it looked like “sudo kpartx ‘/home/ubuntu/Desktop/retropie-rpi2.img'”, since I’ve put my file temporarily onto the desktop of my virtual machine.

The next two steps never gave me any trouble. I just copied “sudo mount /dev/mapper/loop0p2 /mnt” and “sudo sed -i ‘s/^\/dev\/mmcblk/#/g’ /mnt/etc/fstab”

Next thing that really had me confused because this wasn’t specified in any of the tutorials that I read through was “converted_image_for_berryboot.img”. I thought I had to change this to a filepath or to another name or something. But apparently you can just leave this as it is.

Afterwards I unmounted the drive and followed up the final command by typing “sudo kpartx -d” and dragging the original file to the terminal window so it automatically adds the filepath and I was done.

After I was done however I did lose the file because none of the tutorials mention that file appears in your home folder.

I’m sure I’ll be able to take what I’ve learned and apply it to other OS, as I see fit.

I hope one or more of the things I struggled with are the cause of your problems and I hope it helps :)

Good luck!

I’ve succesfully installed it on another raspberry pi today without a hitch.

The first thing that comes to mind. Have you tried it on another SD card? or perhaps you can use the berryboot option to install it onto a USB stick.

Have you checked how much room is available on your SD card?