It also hinges on the kernel, the newer SFOS versions have updated systemd which requires newer kernel or it won't boot. There's work going on to make a kernel adaptation for 3.5.3 but it is progressing slowly, mainly because people have not got much time to work on it... I should check some boot problems with serial console but I have mislaid my serial dongle and I'd need to build a new one, when I have time.