I have uncovered a bug in ioman_flushSector().
This function will return an error code of -1 when the write to the sector succeeds. This causes ioman_flushRange() to exit after the first cache buffer is written.
I have attached my version of ioman.c which is from the 0.2.7 release (and the same as the 0.2.8 release).
This code is being used on a AVR - CAN128 with sd cards.
alan dot wood at vectek dot co dot nz