Arch does not boot (MacBook Pro, rEFIt)

Question

Several months ago I installed Arch on my MacBookPro (5.1, late 2008) in dual boot with Mac OS X 10.7 (Lion).
Everything was fine until last Friday when, after a forced shutdown, ArchLinux refused to boot and showed me a black screen instead (I use rEFIt).
I followed several forum suggestions, mainly consisting in the reflagging of the boot partition (using both fdisk in Mac OS X and parted in Linux) and in the reinstallation of GRUB. After some work, nothing changed: Mac OS X works fine, whilst Linux still offers me a black screen. After few seconds of black screen, the laptop reboots, and rEFIt shows me the same options.
Does anyone have any suggestion?
Thank in advance for any help I can get
Alessia
This is the output of the rEFIt Partition Inspector tool:
*** Report for internal hard disk ***
Current GPT partition table:
# Start LBA End LBA Type
1 40 409639 EFI System (FAT)
2 409640 200228415 Mac OS X HFS+
3 200228416 201497951 Mac OS X Boot
4 207269888 207464447 GRUB2 BIOS Boot
5 207464448 247463935 Basic Data
6 247463936 271464447 Basic Data
7 271464448 488396799 Basic Data
Current MBR partition table:
# A Start LBA End LBA Type
1 1 488397167 ee EFI Protective
MBR contents:
Boot Code: GRUB
Partition at LBA 40:
Boot Code: None (Non-system disk message)
File System: FAT32
Listed in GPT as partition 1, type EFI System (FAT)
Partition at LBA 409640:
Boot Code: None
File System: HFS Extended (HFS+)
Listed in GPT as partition 2, type Mac OS X HFS+
Partition at LBA 200228416:
Boot Code: None
File System: HFS Extended (HFS+)
Listed in GPT as partition 3, type Mac OS X Boot
Partition at LBA 207269888:
Boot Code: None
File System: ext2
Listed in GPT as partition 4, type GRUB2 BIOS Boot
Partition at LBA 207464448:
Boot Code: None
File System: ext4
Listed in GPT as partition 5, type Basic Data
Partition at LBA 247463936:
Boot Code: None
File System: ext4
Listed in GPT as partition 6, type Basic Data
Partition at LBA 271464448:
Boot Code: None
File System: ext4
Listed in GPT as partition 7, type Basic Data

Answer 1

alesssia wrote:The rEFInd's auto-detection shows a generic Linux OS bootable from a generic HD. When selected, Tux is shown, followed by a grub line (that is "GRUB loading"), then by a black screen. Finally, the rEFInd menu shows up again. This is the same behaviour showed by rEFIt and the reason because I used stanzas.
That description indicates that you were launching a BIOS-mode version of GRUB, and that it failed for some reason that's almost certainly GRUB-specific (bad configuration file, missing modules, etc.).
After playing with the EFI shell I was able of fixing the Arch stanza, finally finding an error that should be expected:
Starting vm-linuz-linux
Using load options root=UUID=e6db22f2-e5bb-4933-bba7-20be86db00if ro quiet initrd=initramfs-linux.img
Error: Unsupported while loading vmlinuz-linux
In fact, I'm using a 32-bit version of Arch on a 64-bit EFI.
That's the problem, then. On a 64-bit EFI, rEFInd can launch 64-bit kernels but not 32-bit kernels.
I’m currently trying to fix my hybrid MBR, but despite all my efforts with the gdisk and the gptsync (in rEFInd) tools I always end up with the behaviour described in the first lines of this post: “Grub loading...”, black screen, then rEFInd menu again
I'm not sure what's wrong with that, but I can say with some certainty that it's a GRUB issue. (That's not to say that the solution is in the GRUB configuration; adjusting the hybrid MBR might fix it, but I'm not sure precisely what to suggest.)
I have no idea about how to proceed. Perhaps (re)installing the 64-bit version of Arch is the only possible solution, but I’m scared by all the painful configuration steps that will follow a fresh installation...
As you suspect, installing a 64-bit version of Arch should fix the problem. For that matter, a 64-bit kernel with 32-bit userland should work OK, although that might be tricky to maintain -- I imagine that pacman would try to "upgrade" you to new 32-bit kernels every now and then. Still, it might be worth giving it a try. If you do, I recommend installing a kernel, initrd file, and kernel modules (in /lib/modules) outside of pacman. Install a kernel that's slightly behind whatever is current in pacman. That way, even if pacman upgrades your kernel, your 64-bit kernel will be untouched. You can then upgrade your kernel manually whenever it's convenient or desirable to do so.
Another option is to install a 64-bit version of EFI-mode GRUB, ELILO, or SYSLINUX, and have it launch a 32-bit kernel. I know this is possible because I've done it in some test installations, but I don't recall offhand which boot loader I used, so I can't promise that all three of the ones I mentioned would work. If you go this route, you'll end up with rEFInd to select OS X or GRUB/ELILO/SYSLINUX, which you can then use to select your Linux kernel (or set a very short timeout to launch the kernel more-or-less immediately). See my Web page on EFI boot loaders for Linux for my thoughts on each of these boot loaders.