I have not looked into it all that much. But seems that UEFI basically allows booting without a bootloader. Here is some gentoo wiki info in it: http://wiki.gentoo.org/wiki/EFI_stub_kernel And Greg Kroah-Hartman talking about it a bit: http://kroah.com/log/blog/2013/09/02/booting-a-self-signed-linux-kernel/ I am looking forward to making a little HOWTO, for this subject and also for using `mkdiskimage' with syslinux and vfat ( which i had a lot of fun playing with last night).
However it would be nice to have UEFI all handled by syslinux. So as to maintain some backwards compatibility with older kernels.and perhaps avoid the need for a local run of `efibootmgr', and/or a special kernel build with: [*] EFI runtime service support [*] EFI stub support [*] Built-in kernel command line [*] Initial RAM filesystem and RAM disk The last two of which, are hardly trivial changes. Totally would have to re shape initramfs making and updating systems, to have a kernel src directory handy for a user end automatic rebuild of the initramfs in the event of changed or added boot time modules ( think adding LVM or an encrypted LUKS container). I don't know if this is possible to ask this of syslinux, but if it can be done, that would be awesome.
Am 22.01.2014 15:25, schrieb Dean Graff:> I have not looked into it all that much. But seems that UEFI basically > allows booting without a bootloader.It does. In fact I usually use preloader.efi (with keytool.efi and hashtool.efi for secure boot) and gummiboot.x64.efi to boot EFI stub kernels on x86_64. But until short time a go I had no idea someone would try to sell 32 bit UEFI on computers with 64 bit processors.> I am looking forward to making a little HOWTO, for this subject and also > for using `mkdiskimage' with syslinux and vfat ( which i had a lot of fun > playing with last night).On most UEFI implementations EFI boot from USB works from a thumb drive that has a single FAT partition and that even might be bootable on BIOS. Just /efi/boot/bootx64.efi has to be present, EFI reads the FAT filesystem. However, not every UEFI implementation likes this setup. For those machines "my distribution" LessLinux partitions the thumb drive with a GPT partition table and a legacy boot partition and an UEFI boot partition (and several data partitions). Together with gptmbr.bin the thumb drive is bootable on BIOS and UEFI. A big advantage of this layout is that it can also be used on hard disks that can be booted either via eSATA or USB-SATA adapter. If requested I'll write a tutorial on this kind of layout. But so far I have absolutely no experience with 32 bit EFI. In the past I could simply declare Macs with 32 bit UEFI as "unsupported" or "might work - untested", but with clover trail/bay trail my customers will ask for 32 bit UEFI support. Regards, Mattias -- Mattias Schlenker - Redaktion + EDV-Beratung + Linux-CD/DVD-Konzepte August-Bebel-Str. 74 - 04275 LEIPZIG - GERMANY Bitte fuer geschaeftliche Telefonate vorzugsweise die VoIP-Telefonnummer +49 341 39290767 verwenden, da ich diese aufs Mobiltelefon routen kann!
Mattias Schlenker wrote:> Am 22.01.2014 15:25, schrieb Dean Graff: > > I have not looked into it all that much. But seems that UEFI basically >> allows booting without a bootloader. >> > > It does. In fact I usually use preloader.efi (with keytool.efi and > hashtool.efi for secure boot) and gummiboot.x64.efi to boot EFI stub > kernels on x86_64. But until short time a go I had no idea someone would > try to sell 32 bit UEFI on computers with 64 bit processors. > > > I am looking forward to making a little HOWTO, for this subject and also >> for using `mkdiskimage' with syslinux and vfat ( which i had a lot of fun >> playing with last night). >> > > On most UEFI implementations EFI boot from USB works from a thumb drive > that has a single FAT partition and that even might be bootable on BIOS. > Just /efi/boot/bootx64.efi has to be present, EFI reads the FAT filesystem. > [...] > If requested I'll write a tutorial on this kind of layout >Yeah I mean if you could write a guide on how to do this, that would be really great. thanks, dean