Device mapper is a kernel subsystem that allows creating virtual block devices and mapping them to real devices.
You can for example create a device called /dev/dm9 which is a device of size 4GB starting at 24GB of /dev/mmcblk0. This way, even if you don't have an mmc block device for this partition, you can still use it.
kpartx is a tool that automates this. You point it to a block device, and it creates a dm device for each partition on the device, regardless of partition number limitations of the underlying block device driver.
Yeah I had figured I could use a DM device and with "you can't mount them" I meant "through MMC device"
Unfortunately device mapper add an extra layer of complexity that i prefer to avoid.
kpartx exists compiled for N900 ?
Can I boot from dm device ?
Response is yes, but on Maemo (power kernel) dm device is a external module so I need an initrd or a custom kernel with dm device embedded to boot from a dm device
When I want to boot an alternative os (like Nitdroid, Kubuntu, ...etc), others problems will appear ?
U-Boot can see these partitions (i.e for loading a kernel from mmcblk0p8) ?
