So it could be a solution... With 2.00Beta11, I begun to upload music, and it hanged up after a while. When reboot, it sayed again "No hard disk found". I saw somebody said that for upload hudge quantity of music, it's bether to run a non-beta firmware, so i tried again to downgrade to 1.01. From that time, it has not been possible to upload any firmware, i've tried all of them. Even changing the computer and SO (W2K->Me) and all the COM parameters. Even i've fixed a ground cable to my player. Nothing.
The program begins to "finding pump", and when the blue line reaches about 20%, it changes to "Selecting pump devices" and hangs. In the moment of the change, the blue "link" light besides become off, it was on the rest of the proccess from the player was turned on. No ethernet or USB cable is plugged, only serial (¿?)
I was confused and one of the first times, i could upgrade it to a MK1 version, when it is a MK2a (see some posts before) so the link light was on too. It has something to do with it?
After that, i could upgrade to 2.00b11 and a battery symbol was always on on the screen. I'm ussing a PC power suply, since the mains Rio sent to me was an american one. I belive my PC power supply is strong enough to supply amperes to 4 o 5 Riocar.
When running on this firmware, it hanged too while it was uploading some music, and that's how I am now. I've tried at least 15 times with different settings.
I don't see any light at the end of the tunnel... Any idea?

Thanks a lot:

Miguel Pelaz. Madrid.