Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I am searching and not finding the right way to do this. Please note, I don't think I'm trying for anything strange here. I just want to make a bootable USB stick of a single OS that happens to be larger than one DVD and happens to be larger than FAT32 will allow for in a single file.

On our slow connection I spent a long time downloading CentOS 5.9's two DVD ISOs:

CentOS-5.9-x86_64-bin-DVD-1of2.iso  (4.4 GB)
CentOS-5.9-x86_64-bin-DVD-2of2.iso  (718 MB)

I have a USB stick that I want to somehow get these two ISOs on. Since the first one is 4.4 GB, I can't use ISO2USB because it insists on FAT32. I cannot find an alternative that lets you specify more than one ISO image--of the same distro, I'm not trying for some fancy multi-boot thing--to put on the same stick.

I guess I should have downloaded the CD ISOs, but I thought I was "saving time" because then I wouldn't have as many files to run through the md5 checker. There's no IMG file of the whole thing (only a net install version, which I don't want--I want to pre-download everything) otherwise I would've gone for that. So, given that I have these two DVD ISOs, how can I get them on a stick that will boot and make use of both of them properly to install CentOS somewhere?

Again, I don't think this is anything out of the ordinary, yet I can't find software/docs that seem to support this. Am I stuck re-downloading everything in CD-sized ISOs just to do this?

I found this, but it doesn't run on Windows. I am using Windows to prepare the stick.

share|improve this question
You normally would just place all the files into a single folder. There are other applications to convert an iso into a bootable device. – Ramhound Jun 26 '13 at 15:04
@Ramhound, What do you mean? I downloaded them into a single folder. Unetbootin and UUI and LLUC all seem to only select and deal with a single file. Or do they secretly make use of other files and know their naming scheme? Sorry, I'm not sure what to make of your comment. – Kev Jun 26 '13 at 15:11
Are you saying the contents of the iso is a single file? – Ramhound Jun 26 '13 at 15:42
@Ramhound, no. I don't feel this is some strange question. It's a large distro spanning more than a single DVD. Hence, two ISO files, meant to be burned onto DVDs. ISO2USB will take 7 CD-sized ISO files and put them on USB, but I cannot find anything that will take these two DVD-sized ISOs and make a bootable, installable USB stick. – Kev Jun 26 '13 at 19:26

No. Download the netinstall image. Create two partitions on the USB stick, write the netinstall image to the first, and copy the DVD ISOs to the second. When the installer prompts you as to which source you want to use, opt to perform a hard drive install and point it at the partition containing the DVD ISOs. The installer will then proceed to loop-mount the images and grab everything it needs in order to proceed.

share|improve this answer
Ah, thank you, I will try this out. (I had just finished trying to use the first ISO with UUI, then using 7zip to put the contents of the second ISO on the stick also, but then certain files (.discinfo and TRANS.TBL) it wanted to overwrite, and I figured this would cause problems later either way.) – Kev Jun 27 '13 at 11:41
Okay, the step of "create two partitions on the USB stick" seems to be quite involved, at least on Windows 7:… So, because I happen to have a non-Windows machine around, I might try that for the partitioning step. – Kev Jun 27 '13 at 12:06
That didn't help. Apparently I cannot get Windows 7, even with the help of an external computer, to see, on one USB stick, a FAT partition and an NTFS partition, without getting into registry hacks and fake drivers, which I am unwilling to try on this machine, since it's borrowed. +1 for the idea, but it looks like I have to get CD-sized ISOs. Also it's unclear whether CentOS would even be able to read the second partition if it's NTFS, and if it's not, we again have the FAT32 filesize problem. – Kev Jun 27 '13 at 14:18
(After all, if CentOS can read NTFS okay, then why doesn't ISO2USB allow for NTFS volumes?) – Kev Jun 27 '13 at 14:27
up vote 1 down vote accepted

Unfortunately, you can't, for the reasons discussed in the comments. Your options are:

  1. Burn them onto two DVDs.
  2. Download the CD ISOs and use ISO2USB. (This is what I ended up doing, and it worked, unlike my other answer.)
  3. Download the net ISO and have the rest of the components you need be downloaded at the time of installation.
share|improve this answer

You can merge the DVD ISOs by:

  1. using Universal USB Installer on the first ISO (choosing the "Try Unlisted Linux ISO" at the bottom of the list so that it will actually show up)
  2. using 7zip, extract the second ISO onto the stick as well, choosing "rename" only for the TRANS.TBL file within the CentOS subdir (not the one in root--it has a subset of the one from disc 1--nor .discinfo which is taken care of in step 4 below)
  3. cat the TRANS.TBL files in the CentOS subdir to merge them (looking at Wikipedia this seems like a viable option), sorting them just in case that's part of the spec, and leaving a blank line at the end (i.e. file ends with exactly two newline sequences)
  4. change the .discinfo file's line reading 1 to 1,2 a la this page
share|improve this answer
Nope, this also doesn't work. It doesn't get very far before this screen saying "Select the file which is your driver disk image" which rejects most files on the stick and for one or two will abnormally abort the installation process. – Kev Jun 27 '13 at 20:51

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .