Hi stefsom, what do you mean exactly? Is it that all Philips burners firmwares are incompatible with each other, or is it that the flashtool does not allow to flash the firmware of a higher burner (i.e. 16x)?
Yes, the flashtool will prevent it It will compare 2 checksums. 1. From the cdrw drive itself (in your case cdd 4851) with 2. the firmware file (cdd4851) If you open the firmware fiel with a HEX-Editor you will find the string "philips cdd4851 flash file" 2 times. At the begin and in the middle.
Now if you are smart you can take the firmware from the cdrw1610a (cdd4911) and rename the 2 strings to cdd4851 . BUT the cdrw1610a uses another chipset teh the pcrw1208k.