Making Custom USB Install Media

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Hey List,

I apologize for how broad this may be, but hopefully someone here can help me out. I need to make custom kickstart installers to be used in the field to install microservers (Intel NUCs, EFI boot) that don’t have optical drives and may not have internet connections.

I can make a custom ISO just fine using the pretty common steps, specifically following what’s here:

My custom kickstart is on the disk, and along with all my packages, and everything works great on a VM as a CD image.

The problem is I can’t get this to install from USB. I can get it to boot from USB using the isohybrid tool, but the installer fails, can’t find the squashfs image. I don’t think this is the right way to do it.

I know the CentOS 7 (and I believe 6.5) images have a “special” EFI
partition that I believe is why USB works with the base image. The problem is I can’t really find any information on how this works or how to recreate it. When I run fdisk -l on the image (as a loopback device) I see that the main image is on a partition marked as none, and then there’s an EFI
partition with start and end points actually inside the first partition?
I’m afraid I don’t really know what this is doing, or how to go about recreating.

Can anyone explain this to me or point me at some documentation? Am I
missing something obvious, like say the old Revisor tool that I should be using to make my life much easier?

Any help would be much appreciated,


4 thoughts on - Making Custom USB Install Media

  • Almost. I’ve read that, and I can get it to work.

    I guess I could phrase my question as “Given that the default image for
    6.6 and 7.0 do this, how do I make custom media that does it to?”

    When I make custom media, it only works off an actual DVD.

    I need help making custom media that has that USB/EFI magic in it.

  • Well I feel like a fool, but I owe you one anyways. As noted in my message, isohybrid was one of the first things I tried, and it seemed to work, but the installer would bail saying can’t find file, seemingly referring to the squashfs file.

    Now I’m pretty sure it was saying it couldn’t find my kickstart file. I’d modified the menu to say ks