From the command line, the Linux IrDA stack can be adjusted for the buggy Ericsson's with these commands:
# echo 1000 > /proc/sys/net/irda/min_tx_turn_time
# echo 1 > /proc/sys/net/irda/max_tx_window
Use sysctl to automate these parameters, man sysctl and man sysctl.conf will help.
The odd part with these bugs was that the IrDA connection worked (when worker, it was rather unstable) with very strange serial port settings: the parity check bit had to be set to Even instead of the usual None (8E1 instead of the usual 8N1).