Using a PIC18F4550 package for PIC18F2550 compiled code. Any issues?

I am building a product I want to be compatible with the Experimenters Version of PBP3 for a 18F2550. However, the 2550's smallest package is a soic, and this needs to be small. The 18F4550 does come in a QFN, so I was looking at that as a possible replacement. I have done a few tests with Microchip's HID USB bootloader loaded on a 18F4550. It accepts hex files compiled for a 18F2550, and the few tests I did worked fine, operating the standard ports, and using Steve's (updated by Darrel) USB Demo program. I don't need to utilize any more pins than a 2550, I just need the smaller package. (It will always be programmed with the USB bootloader).

Does anyone see any issues with this setup?

Thanks,

Walter

Ground the leftover pins so they do not cause problems.

Hi Walter,
You are probably going to be alright going that way, except for having more memory than you can access, I think if you went the other way it would put the hurt on you.

What does ADC have to do with USB?