kuzgun, A firmware dump is not a full firmware it is missing 10-12 files. It is not possible to extract a full dump.
When your player is in recovery mode it will not accept a dump file you must load a Full Version Firmware. It does not have to be the exact one for your player but it contains the files needed so that you can then load your dump.
You will find some Full Firmware
HERE .
Just to be sure you understand you have to load your friends dump firmware in 2 stages.
1. Load a full version firmware to your player and wait till it reboots.
2. Load your friend dump to your player.
Sometimes you may need to format your player between 1 & 2.
If his firmware is right your player should work ok.
Try using a full firmware that has the same version number as your dump.
You may also have to try a couple.