Why there is no 32bit EFI boot available on current ISOs?

Question

I have an old Macbook 3.1 with a broken disk drive. I was going to throw it to the trash when I found EFIs boot great solution which works from USB pendrive. I was able to install Ubuntu 64bits on it but the issue is that running a 64 OS in a computer with 1G of mem is really low performance.

The question is, WHY there is no EFI/BOOT available in any of the 32bits images available? I have checked in other distros as well. There are comments in Ask Ubuntu posts that state "Use the latest AMD64 (LTS) ISOs, because these definitely contain UEFI bootloaders". Why??

If there is no problem to have it, could somebody help me build it? I am interested in running Lubuntu 32 bits.

I did try building my own /EFI/BOOT/BOOTIA32.EFI based on some old post but no luck so far.

thanks in advance, Hector

Solution

I can't speak to the thinking of the Canonical team that makes these decisions, but my understanding is that it all boils down to the Frankeinstein-monster nature of Ubuntu installation media (and Linux installation media generally). In brief, Linux distribution maintainers don't like creating more installation media images than they must, so they go to great lengths to create images that can be burned to CD-R or written to USB flash drives; and that can boot in both BIOS mode and in EFI mode. Doing this means that they have to take advantage of quirks of these various media, and the whole thing barely hangs together. The trouble with 32-bit EFI support is that one of these contortions (providing multiple El Torito images) pushes many middle-aged 32-bit BIOSes past their breaking points. In other words, a 32-bit BIOS/EFI boot medium won't work on many BIOS-based computers. Thus, to support a 32-bit EFI installation, the distribution would need to create a separate boot image specifically for that target. For more on the technical details, see Matthew Garrett's blog post on the subject.

As a practical matter, see this question/answer for some pointers on getting a 32-bit EFI-mode installation started:

32-Bit UEFI Boot Support

It can be done (I've done it several times myself), but it's not very well-documented.

Comments

[oldfred]

The developers had discussions on whether there even was enough demand for a 32 bit version. Only now with kernel 3.15 or greater is there support for a 32 bit UEFI boot loader.

[Rod Smith]

32-bit Linux kernels have long supported EFI boots; I've been booting my 32-bit Mac Mini in EFI mode for years! The trouble lies elsewhere (see my answer).