Re: How to boot a memory stick image of a hard drive?

[Pascal Hambourg]

Le 08/07/2017 à 09:21, address@hidden a écrit :
>     I am using a Debian distro - Knoppix 6.4.3 - pretty old but known to 
> be reliable.

I know Knoppix only by name but I would be surprised that it does not 
use an initramfs.

>     It sounds like I need to teach that kernel how to find and mount its 
> root filesystem. Previously I would fiddle the MBR with fdisk and 
> eventually get things to run.
>
>     With the USB now in the picture, I am not sure that can be done with 
> that kernel?

If the kernel uses an initramfs, USB host and mass storage drivers 
modules must be included in the initramfs. Otherwise, USB drivers must 
be built into the kernel image (not built as modules).

If you built your own custom kernel which does not use an initramfs, USB 
drivers must be embedded in the kernel image, not built as modules.

In Debian the standard initramfs generator provides an option to 
generate a compact initramfs including only the modules needed for the 
current system, instead of the generic initramfs including all the usual 
storage modules.

Also, /dev/sda may not be the USB stick if the machine has other drives. 
If the system uses an initramfs, it would be safer to use the 
UUID=<root-fs-uuid> syntax to specify the root filesystem.