Ipod not mounting in DFU mode

[CJ1024]

Ok guys, I have a 6th gen (80gb 1.1.2 version) iPod, and I'm trying to install an iflash with a 256gb SD card. I am using an iMac (OS X 10.5) and the sd card is formatted Fat-32; when the iPod is connected normally, it mounts fine. When I put the iPod in DFU mode (hold menu+select until screen turns off), it doesn't mount, and the Rock box utility won't recognize it. System profiler shows it as a usb DFU device with the id #1223, so I know it's in dfu mode. What am I doing wrong?

[prof_wolfff]

See https://www.rockbox.org/wiki/IpodClassicPort

For Windows you can use the patched RockboxUtility, see https://files.freemyipod.org/~user890104/bootloader-ipodclassic-v8-designware/README.RockboxUtility.txt

For Linux or Mac, mks5lboot tool is needed, see https://files.freemyipod.org/~user890104/bootloader-ipodclassic-v8-designware/README.mk6gboot.txt
You must compile mks5lboot yourself after applying this patch: http://gerrit.rockbox.org/r/#/c/1266/

To not to get confused, note that mks5lboot is the new name for mk6gboot, but they are the same tool.