Booting from USB drive - but only in FAT16?
 

Is it possible that an older computer can only boot from USB memory sticks if that stick is formatted FAT16, not FAT32?

I'm experiencing difficulties booting certain distros from sticks, that boot okay when the same ISO is written to a CD and booted from that. The same memory sticks with the same distros on, boot okay from a newer computer. Typically the older computer gives a message saying ISOLinux is corrupt or missing.

In the BIOS settings, there is a checkbox for "USB legacy", which I have ticked "on". Is it the case that some older computers cannot USB boot from anything other than FAT16, or is there a BIOS setting I could change to permit booting from FAT32 sticks?

USB legacy usually is a deal for mouse and keyboard support.

We may need to know more about this system.

What you are really saying is you are using a non-standard install to a usb flash drive. Fat is not a native format unless you did some old zipslack umsdos deal. Since this is an odd install we would have to also look for other issues like syslinux versus isolinux bootability.

Format of a drive is independent of the system. Partition may be of issue.

I started using UNetbootin to make the memory stick up from the original ISO file, but never had a successful boot on the older computer using this method. I have had some success using "dd" in the terminal though.

The computer in question is a Research Machines CL50 laptop, with Pentium M 1.6GHz CPU, 733MB RAM. The CPU doesn't do PAE, so that limits the distros that will work anyway.

The CL50 is currently running Linux Mint 12 LXDE, but I had to write the ISO to a CD and load it from that. I wrote the same ISO to both FAT16 and FAT32 sticks, but no joy.

The laptop reads and writes to FAT16 and FAT32 sticks when just using them as storage. It is just booting distros from them that it has trouble with. My newer desktop PC has no trouble booting with those same sticks.

It's a bit of a mystery that I would like to get to the bottom of. If I want to try out new distros on the machine, I don't want to have to keep writing CDs and DVDs to do this.

The hardware doesn't care at all which file-system is used for booting, since the hardware usually does not even know about the concept of file-systems.
All that the hardware does is searching for a boot-loader in the MBR of the disk/USB device, loading it into memory and starting it. After that happened the hardware is not involved anymore in the boot process.
Which file-systems are supported and which are not is solely dependent on the bootloader. If some machines can boot from FAT16 and some can not I would rather think about a bug in the bootloader than a hardware issue.

So, is it the case then that the bootloader will vary from one ISO to another? Would any bootloader be part of the ISO? Or do different methods of getting the ISO to a bootable memory stick affect the bootloader, like using UNetbootin, dd, or any other boot-from-USB software?

The bootloader on ISOs and USB devices are different. Unetbootin installs its own bootloader (I think it is a version of Syslinux).
It is of course recommended to always use the newest version, since it will have a newer bootloader, where possible bugs may already be fixed, but sometimes it may be worth to try older versions, in the case that the newer version is the one with the bug.
Or try a different program for this purpose, there are several others.
If that all doesn't work I would try it manually with a different bootloader (Lilio or Grub).
If it then still doesn't work it really has to be your machine and not the bootloader, but that would be strange.

Some computers won't boot off of fat32 flash drives
 

Yes, but I don't know how common it is. I personally have several Gigabyte GA-790FXTA-UD5 motherboards. None of them will boot off of a USB flash drive formatted with fat32. It will, however, boot off a flash drive if that flash drive is formatted with something else. So far every file system (other than fat32) I've tried has worked:

• fat16
• NTFS
• ISO 9600

Note that if you have Windows you can easily covert a flash drive from fat32 to NTFS with this command (where X is your drive letter):

It is always best to use dd when creating bootable drives from CD/DVD distros. :)

Most CD/DVD are created as hybrid, which means they can be used from optical drives or disks.

These are created using a program called isohybrid, so if you have a distro that won't boot after dd'ing it to a pendrive, try running isohybrid on the .iso file first.

My regular distro, antiX, tends to work on most old computers. http://antix.mepis.com/index.php?title=Main_Page

Are you sure about that. Many, but not all, Pentium M processors report that they do not support PAE when in fact they do. If you pass the "forecpae" option when booting up the installation CD the installation will go if your Pentium M really does support PAE. See:

https://askubuntu.com/questions/4540...out-pae#460824

It's worth a try and will allow you to update to a more modern distro. I discovered this by accident when installing Debian with XFCE on an old Pentium M laptop. Debian still supports non-PAE processors. Debian's installer automatically detected that my Pentium M really did support PAE and installed the PAE kernel. I've since been able to boot all the PAE only installation media I've come across by using the forcepae boot option.

It was method A on the How to install SystemRescueCd on an USB-stick page where I first tried using dd. It was following these instructions that made me realize that my old Gigabyte GA-790FXTA-UD5 motherboards can boot off of ISO 9600 flash drives.

The downside to this is that (AFAIK) you can't write to an ISO 9600 flash drive. That's why I prefer to use fat (fat16 in my case), it's easily writable from both Linux and Windows. Because of my desire to have a fat16 file system dd isn't the best choice for me, but it was the easiest. I would recommend it as the best/easiest way to create a bootable USB flash drive from Linux if you don't need write access to your flash drive.

kilgoretrout,

TYPO: forcepae

your laptop is NOT so old as to need anything with fat16


i have a EVEN OLDER!!! desktop from 2000/2001 ( 16 years old ) running ScientificLinux 6.8
however RHEL/CemtOS/SL 5.11 would not need any custom hacking to run on the hardware

this machine came with a p4 1.9 ghz and 256 meg ram ( now has 1 gig ram) and a antique gforce2 card

so on your4 Pentium Mobile 32 bit CPU
ext3 /boot partition will work just fine for Cent5.11 or ext4 for CentOS 6.8
even a fat 32 would work

Original post 10-15-12, 05:30 AM