According to Modaco’s site, here is what we know about the porting process so far:

• If you rebuild the boot image replacing the kernel it runs. I’m running my own custom kernel with himem and bits.
• The system.img doesn’t fit on the N1 (!), it’s nearly 200MB. I booted by moving some stuff off the system partition.
• The trackball works.
• The 4 bottom keys work.
• The proximity sensor works.
• The LED works.
• The light sensor works.
• The compass and G sensor work.
• The camera works fine and is great with face recognition and touch focus.
• The FM radio loads, but makes no sound / finds no stations it seems. Maybe we need Desire radio ROM?
• Flash 10.1 is included and works well.
• It’s FAST!

Source: Into Mobile