I don't kow where is the boot on my usb drive which can be not bootable

[Serge Noiraud]

Hi,

I have one usb devices with one to four luns.
Operating system like linux can be installed on a lun.
I don't know this lun. No problem for that, Grub is OK.
It is an installer decision and I can't make this mandatory.

My problem : Some machines have no usb boot possibility.
For that, I use a CD-ROM.
I don't want to have one cd-rom for each lun and for each
kernel installed on the usb devices.

My questions :

How to know if I have one or multiple grub installed ? and on what lun ?

Is it possible in this case to generate a dynamic grub configuration
file depending on what I found on these luns ?

I could develop this if it is possible.

many thanks in advance.

--
Serge Noiraud