casper toram specify live-media device

Question

Is there a way to specify the device on which the live-media will be found?

I have the kernel and initrd in my EFI System Partition. The live-media filesystem is in an NTFS partition on the same (USB) drive. grub2 does not have NTFS support built in. When booting with Secure-Boot ON, grub2 will not load modules, so its "search" command is not able to find the NTFS partition, and it is unable to load the kernel and initrd from that partition.

I have tried

1. linux kernel live-media-path=path-to-casper-directory
2. linux (hd1,msdos1)/kernel live-media-path=(hd1,msdos5)/path-to-casper-directory
3. linux (hd1,msdos1)/kernel live-media=/dev/sdb5 live-media-path=/path-to-casper-directory

4. set root=hd1,msdos5
   linux (hd1,msdos1)/kernel live-media-path=/path-to-casper-directory
   

Most of those boot, but fail to copy the live-media filesystem to ram:

    Begin copying live-media to ram...
    Not enough memory (4GB > 187GB) to copy live-media to ram

(this is an approximation of the messages in /var/log/casper.log)

I've seen mention of the "live-media=" kernel option to specify the live-media device, but I've also seen mention of that option not working. I've tried looking through initramfs-tools/scripts/casper for some clue as to the proper format/protocol for specifying "live-media=" -- I failed.

Answer 1

live-media=/dev/sdb5 works as advertised.

I misinterpreted the reference to "187GB needed" as indicating that casper had latched onto the wrong (possibly unformatted) partition, since I expected it to need 1 GB if it copied the filesystem.squashfs file, and 3 GB if it copied the contents of the file system represented by that file.

I had managed to repeatedly read the description "copy the read-only media" and interpret it to mean "read-only file system". Since it really did mean "media", and I was burying my casper directory in an NTFS file system with a whole lot of other crap, it really did want to copy 187 GB.