Dazza-E-, Yes FAT32 seems to be ok on newer players. Can you access the player through Explorer.

Yes I Can, ive got a back up of my original mp3 player firmware but ive just extract the one that is currently on it (using the software before s1fwx) and then repaired that on one of the lines I got the following...

UI30.RES 2.58MB 4DBB56B2 <--- Invalid Check Sum (could this be why your firmware isnt working correctly and is this why I can't flash it with my old firmware ?)

Ok I just ran error check via windows explorer and that completed without a problem should I try and change the UI30.RES to something else ? and then try and re flash the mpx player with the new firmware ?

Dazza-E-, Which one is on it?

The firmware which the invalid checksum is the one that is in your actual recovery section thats the one ive flashed my mp3 player with. Am actually sifting through the firmware (the one ive just extracted, one from recovery section using s1res) and ive noticed that from UI30.RES/ICON/pmdlld to UI30.RES/ICON/pmdwait2 there are no images there just black screen or just blue is this correct ?

Ok my player is now in recovery state... when i try to put my backed up firmware on i get the following message:-

"Invalid firmware upgrade file"

Yet the two files are the same version as your one in the recovery section and also have the same files is there anyway I can edit the UI30.RES or just update that section of the firmware ?

Dazza-E-, I just loaded the firmware on to my player and then did an extraction and ran repair.bat and get no checksum warnings. But it could be the problem.

Ok just so that I fully understand.
You made a backup of your firmware using s1res and ran a repair.
You tried to change your theme by uploading a mac themed firmware. Then your player would not turn on but was recognised by Windows.
You followed the dead player guide and Windows recognised your player as an ADFU Device.
You then loaded 3.5.37v2.1b FM.fw in recovery mode with success .
As per guide you turned your player off and on and waited 30 sec.
You then tried to reload your backup but got a device not connected error message.
You formatted the player and then tried to upload your backup but could not.
You can still upload 3.5.37/v2.1b FM.fw but no other firmware.

OK this is my understanding of what you have done so far.

Yes that is all completely correct just trying the final steps again gonna reformat and then try the mp3 tool again. it seems the only way I can get to recover anything though is by using the tweesers and shorting the chip. wont let me do it any other way.

did them last steps again and got... device switching failed, please try again.

I have this funny feeling its the actually format (FAT32) which is the problem here... ive sorted the bad sector out by re downloading the 3.5.37v2.1b FM.fw. When am connecting the mp3 player into my computer its saying I have two drives a E:/ and a H:/ the H:/ one is the actual mp3 player but whats this E:/ one all about ?

I dont have one connected to my computer should I close this one down and try the tool again. Am at the moment formating the mp3 player to a FAT partition.