I thought the problem that some people were having using uart0 on 1284P boards was pretty much solved with changing the low fuse byte to use full swing oscillator option?
#bobuino.bootloader.low_fuses=0xff
bobuino.bootloader.low_fuses=0xf7
I didn't require that change as I never saw a problem using optiboot on my CrossRoads through hole 1284P PCB using uart0 even with uploading long sketches, but I made the change anyway.
Lefty