Sailfish OS was built by Jolla, a company formed by ex-Nokia employees who worked on the original MeeGo project. Because Sailfish OS shares the same DNA as Harmattan, porting it to the Nokia N9 was a top priority for early developers. Features of Sailfish OS on N9:

Most custom ROMs require you to unlock the bootloader and install (or Moslo). Ubiboot allows you to multi-boot multiple OS partitions without constantly re-flashing the NAND.

To use any custom ROM link or firmware file for the Nokia N9, you need specific desktop flashing utilities. You must hunt down these tools alongside your ROM files: