If your burner cannot burn CD-R media anymore, it is very unlikely that a firmware upgrade will help.
The Pioneer 112/212 series had problems with the laser used for burning/reading CD media; a significant number of the manufactured units would have the CD laser die rather quickly. There have been some threads in this forum on that subject in the past - you could try searching for them if you're interested.
If your drive also fails to read CD media, then I think this is the most likely reason for your problem.
If the problem is only with burning, you might consider trying other CD-R media.