Ok, now I got it . The basic install tutorial for Ubuntu will lead you to using a hybrid partition table, that is not necessary in MacOS.
Quackers, since I already had a +- working dual boot Mac/Ubuntu, I wanted to try first (before trying your solution) if I can fix the partition table from a hybrid to an only GPT using this thread on fixing the partition table after a basic Ubuntu install. However, I am not sure I managed to configure all the description in the thread correctly as some steps are little tricky for newbies...
At least I am able to dual boot nicely and in the process managed to fix my login icon issue (see my thread).
How can I check in ubuntu if my partition is GPT? I used sudo gdisk /dev/sda and got:
Is this alright? thanks for comments, really appreciate it!
GPT fdisk (gdisk) version 0.8.7
Partition table scan:
BSD: not present
APM: not present
Found valid GPT with protective MBR; using GPT.
Command (? for help): p
Disk /dev/sda: 236978176 sectors, 113.0 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): 000046A1-0232-0000-8139-00007D720000
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 236978142
Partitions will be aligned on 8-sector boundaries
Total free space is 3757 sectors (1.8 MiB)
Number Start (sector) End (sector) Size Code Name
1 40 409639 200.0 MiB EF00 EFI system partition
2 409640 195959095 93.2 GiB AF00 Macintosh HD
3 195960832 203771903 3.7 GiB 8200
4 203771904 217444351 6.5 GiB 8300
5 217444352 236976127 9.3 GiB 8300
Command (? for help):