Bootloader problem.

[mister_e]

how about if you remove the config fuse? BTW they're not supposed to be there. You need to set them ONLY when you load the bootloader firmware. More than often, the default one are set correctly.

[Bruce]

RB3 is the LVP pin. Make sure you're not setting LVP ON at the time you program the boot-loader .hex file into your F877 with your PicStart Plus.

[Peter Oors]

RB3 is the LVP pin. Make sure you're not setting LVP ON at the time you program the boot-loader .hex file into your F877 with your PicStart Plus.

This was indeed the problem. Now it works fine.
Thank you Bruce.

Mister_e, leaving the config fuse didn't harm.....

Thanks to all of you.