There hasn't been any overly difficult parts. I'd say the most difficult one has to be either AML interpreter because the ACPI specs are very badly written or the USB stack just because the size of the specifications is so large with a lot of cross referencing.
There hasn't been any major roadblocks. Sometimes I give up on a feature and come back to it maybe month or two later though.
There hasn't been any major roadblocks. Sometimes I give up on a feature and come back to it maybe month or two later though.