LOL, did it and is working.
I don't know what did it but it is functional.
All I did was format to FAT 32 instead of keeping NTFS.
Made the partition 3 Gig.
Made it my first partition on the drive.
Now it is possible to read and write covers to USB:/usb-loader/covers.
(this is the base path of CFG usb loader on my hard drive and written in config.txt)
Thanks for your help.