For now you have to choose between APFS support build in or Theme build in both of them won´t fit into most modern ROMS. In case of a missing Theme just add OzmosisHorizontalTheme.bin.zip to the OZ Folder on your EFI Partition and perform a NVRAM Reset and you're good to go...
Hello, A little back !! Regarding the theme, it must actually place it in OZ, but it must above all rename it to theme.bin!
Concerning the installation of High Sierra, I made several tests, with APFS:
With F12, I select my USB key, the installation goes well, the PC restarts, I complete the installation, but on the second reboot, my SSD, is no longer seen by the bios (except P0xxxx).
I have the impression that the partition EFI (Fat 32), is not mounted!
At the start of the bios, I have this message:
efi_container_create:858: LoaderImage->Dev iceHandle = 0xdd1d0918
nx-dev_init:860 warning: superblock indicates jumpstart record but this driver was not loaded from that partition
In the meantime, I came back on sierra !! I'm afraid that the bios ozmosis I knew, died with the arrival of High Sierra