hello . I just registered to thank you for these tips.
My mini 2nd gen was consistently crashing into "do not disconnect" everytime now so I had to uninstall rockbox after the battery drain (the only way I could reboot) so I use the GUI util but only did (ironic) a
COMPLETE unistall > lo and behold it crashed again

but this time to the screen indicated by the OP. I didnt read the directions in the bottom as I tried it a couple of times after reading this thread > well sometimes it would work but I either didnt do it as fast I should have or it really did take a couple of times (like a PC boot up on BIOS pressing f2) then the switching of the hold on and off made it easier only takes 2-3 secs to reboot but the trick is to time the "select+play"
EVENTUALLY > I got to the screen with a BIG check mark saying DISK MODE hooked it up the pc and BOY WAS I RELIEVED! > did the
UNINSTALL BOOTLOADER and vhalla back to stock
rockbox just slowed down my ipod + slow boot +battery drain
...just could bare waiting on it > eventually it crashed enough times for me to bid it farewell
