Problem with tsst h-492a

I have a samsung tsst h-492a combo drivewhich was working perfectly till i installed a firmware upgrade from the manufacturer’s update site. Now I have major problems with it.
The drive does not read cd-r’s written in track at once mode. The writing process fails 90% of the time and seems to work only in the disk at once mode.Though dvd-rom’s and cd-roms are read perfectly well. Kindly someone tell me what could be the problem. is there a way to downgrade firmware. my system specs are

Pentium 4 1.7 ghz (wilammete)
632 mb ddr(pc 2100) ram
seagate st3160021a 160 gb 7200 rpm pata hard drive
intel 845 chipset (with intel application accelerator installed).
samsung tsst cd/dvd h492a combo drive( intial firm ware tb02, now tb08)

i use nero ultra edition( ver 6.6) for burning. it sometimes shows power calibration error.Though the burning fails the cd remains useful. The end result is that i have to repeat the process 5-6 times before i get a succesful burn. Has this got something to do with the SMPS.