thanks a lot for the "boards.txt" file. I used it in combination with the earlier posted optiboot code (optiboot_atmega328_pro_8MHz.hex) and an UNO R3 as a programmer for the 3.3V 8Mhz ProMini board. Uploading the bootloader worked very well. However, when trying to upload a sketch via the Ardunio IDE, I got the following error message: "avrdude: Yikes! Invalid device signature. Double check connections and try again, or use -F to override this check." Does anyone have an idea how to tackle that problem?
Ray, what are you using to program the Pro Mini? I assume that worked OK before you burned the new bootloader? Which version IDE are you using?