Re: Assortment of Issues with EFI on Mac

[Vladimir 'φ-coder/phcoder' Serbinenko]

On 31.12.2011 09:36, Jake Thomas wrote:
> Thank you Vladmir for the response : D ! I'm new to the Grub mailing lists, and 
> these bugs have been on my mind for some while.
>
> My experiences differ with a couple things you said. You said that you cannot depend on 
> drive order. One of the few things that has worked 100% of the time with my adventures in 
> Grub has been Grub calling the hard drive (by "hard drive" I include thumb 
> drives) it is on the first hard drive. In all my experiences, regardless of machine and 
> regardless of whether using EFI or BIOS, the hard drive with Grub on it is recognized by 
> Grub as the first hard disk. That's the one thing I can count on.
Not true. While some implementations have this behaviour it's not 
specified or universal
>   What if the UUID changes?
Then you need to update grub.cfg
>   What if I have more than one thing with the same UUID?
Then you're just asking for trouble on several levels. Ranging from 
GRUB, going through initramfs, fstab and some FS drivers themselves 
(e.g. btrfs can't work in such conditions)
>   In the bug I describe where Grub boots the internal instead of the thumb 
> drive, Grub is disobeying my instruction from the grub.cfg file to boot (hd0, 
> [whatever]). hd0 is my thumb drive. I have confirmed this with ls (list) at the 
> Grub command line. Listing the contents of a partition in hd0 shows contents of 
> my thumb drive, not the internal hard drive. Then it boots the internal instead 
> anyways, even though I said to boot hd0, which I just confirmed is my thumb 
> drive and not the internal.
how initramfs finds root is outside of GRUB's scope and I suppose that's 
where your problem is. I guess GRUB loaded kernel and initrd from stick 
but it mounted the internal root. Again duplicated UUIDs=trouble and 
isn't supported by anyone.
> Ok, I messed up on technical terminology with the "carriage return." I meant whatever it is you get from 
> pressing the "enter" key while in a text editor. That is, vertical space. If there is any vertical space 
> after the last "}" from the last menu entry, grub doesn't load that config file. You would have to go back in 
> and delete the vertical space at the bottom so that the "}" is the very last line. Not just the last visible 
> line, the last line period. You can check by using the arrow keys to try and go down to the next line. If you get to a 
> blank line, you need to delete that vertical space. If the cursor doesn't move, you're good.
Unable to reproduce. Check that you have latest version and that you use 
unix endline style, not dos/windows or mac one
> Why shouldn't the normal mod be baked into the image? Isn't it vial for it to be baked 
> into the image? How else is it going to come up with a background image and menu entries 
> and not be in rescue mode? I want it to go to the menu automatically. I don't want to 
> have to type "insmod normal". Especially if I am forging a multi-bootable thumb 
> drive for someone who is not a Grub guru.
insmod normal is issued automatically. Use grub-install or grub-mkstandalone
> With my grub.cfg file for 64-bit EFI, even when I didn't change anything in the 
> file at all, behavior of Grub was not consistent across all boots, and all the 
> while the drive mapping stayed the same; hd0 was always the thumb drive. So I 
> know the bug is either in the EFI or in Grub. Not my grub.cfg. It usually 
> works. And I am loading a unicode font file.
Upgrade to the latest version for starters
> New Year's is getting close, maybe already is in some places around the world.
Not here. Cooking is still to be done. Will be unavailable for few days.
> Cheers,
> Jake
>
> Sent from my iPhone
>
> On Dec 30, 2011, at 8:54 AM, Vladimir 'φ-coder/phcoder' 
> Serbinenko<address@hidden>  wrote:
>
> > On 30.12.2011 14:12, Jake Thomas wrote:
> > > //Using version 1.99 of Grub
> > > Hello everyone, I've been meaning to submit these bugs for quite a while now, 
> > > at least since summer, but have been busy with school and hadn't taken the time 
> > > to figure the Grub mailing list out, and was at a loss as to how to go about 
> > > submitting bugs.
> > >
> > > I have been playing with Grub2 on a thumb drive. I didn't know why it wasn't 
> > > booting on the Mac, and, after some research, found out about EFI v.s. BIOS. 
> > > After some more research and head-banging, I made some working grub efi images, 
> > > put them on my thumb drive, and I could boot Linux off my thumb drive on a Mac, 
> > > which uses EFI, not BIOS.
> > >
> > > I encountered some issues.
> > >
> > > One I call the "temptation error". If Linux is on the internal hard drive of my 
> > > Macbook, and I get booted into Grub off my thumb drive via EFI, and I tell it to load 
> > > Linux off the thumb drive, Grub finds the Linux on the internal hard drive too tempting 
> > > and usually boots that instead. The kernel and initrd were the same name and path on both 
> > > the internal hard drive and thumb drive, so it's not like it got possessed and started 
> > > looking around for Linuxes to boot.
> > >
> > > When you are on a Macbook with Linux on the internal hard drive with a kernel 
> > > and initrd of the same name and path as the kernel and initrd on a thumb drive 
> > > with a bootable grub EFI image, and you boot into EFI Grub off the thumb drive, 
> > > it seems to, on average, actually succeed in booting off the thumb drive rather 
> > > than the internal about 1 in every 14 times. It's more like it randomly picks a 
> > > number between 12 and 17 or so, and that's how many more attempts it will take 
> > > to get to the next successful attempt to boot off the thumb drive rather than 
> > > the internal.
> > It's usually a symptom of duplicate UUID or wrong grub.cfg. You can't rely on 
> > drive order. You need to use search -s root -u UUID
> > > Another one is an often patternistic blackout bug. I can boot my MacBook off my 
> > > thumb drive into EFI Grub, select to boot Linux off my thumb drive, and boot 
> > > Linux no problem (unless Linux exists on the internal). Then the next time I 
> > > try, it might black the screen out. In fact, pressing enter or escape or any 
> > > key doesn't do anything, so it actually is crashed-out, rather than the screen 
> > > simply having gone black.
> > > But here's the interesting part: If I save a copy of grub.cfg to my desktop (the one in 
> > > the EFI grub prefix) and then delete it off my thumb drive, and then boot my MacBook off 
> > > my thumb drive, I successfully get to a command line and can boot Linux "by 
> > > hand." Then I can put the grub.cfg back on, and it will work next time. Sometimes it 
> > > follows a simple AB pattern of blacking out, me deleting grub.cfg, getting to a command 
> > > line, me putting grub.cfg back on, Grub booting correctly with a menu and background 
> > > image and all, and then the cycle repeats. Though recently I haven't experienced a strict 
> > > cycle; it's more of a certain probability of blacking out, to which the fix is to delete 
> > > grub.cfg, boot without it, then put it back on.
> > It's possible that it's another symptom of last problem
> > > And here's a couple of minor bugs (but they still ought to be fixed):
> > >
> > > Grub doesn't load a grub.cfg file if it has extra carriage returns at the end. To someone 
> > > who doesn't know this and is making a grub.cfg file by hand for, say, a thumb drive, this 
> > > can cause a lot of frustration; it sure caused me a lot of frustration! Grub only loads a 
> > > grub.cfg file if the last character is a part of the Grub script, usually a "}".
> > grub.cfg has to be in unix-style newline that is \n=LF. There should be no 
> > CR=carriage return at all.
> > > When I boot my thumb drive via EFI on my MacBook, it erroneously, for a brief moment, 
> > > says "error: prefix not set" and then continues loading Grub to a menu with a 
> > > background and everything (unless it blacks out). The prefix is indeed set and can be 
> > > confirmed by command line.
> > normal mod shouldn't be baked into image. Use grub-install
> > > Also, I have experienced issues with iMacs, but don't have enough definite 
> > > testing to really report anything. It wasn't loading the background, had funny 
> > > characters around the menu like it does when the font file isn't present, and 
> > > it was in portrait rather than in landscape, and if I remember right, didn't 
> > > even boot Linux.
> > if you use gfxterm you need to load unifont. If you don't GRUB can't load 
> > background image
> > > I'm a big fan of Grub. I felt like I found heaven on Earth when I started 
> > > understanding it and using it, because I was using syslinux before that (for 
> > > thumb drives). Boy! Support for either EFI or BIOS, the ability to have a 
> > > pretty background image, font of your choice, so many modules for 
> > > anything...it's got so many great things to it! And if these kinks could be 
> > > worked out, it'd be even better. If we really do switch to EFI, they better get 
> > > fixed.
> > That's good to hear. You can drop by in IRC and hopefully we can figure what's 
> > wrong with your system and whether any of it is a bug as opposed to wrong 
> > manual config
> > > Cheers,
> > > Jake
> > >
> > >
> > > _______________________________________________
> > > Bug-grub mailing list
> > > address@hidden
> > > https://lists.gnu.org/mailman/listinfo/bug-grub
> >
> > --
> > Regards
> > Vladimir 'φ-coder/phcoder' Serbinenko


--
Regards
Vladimir 'φ-coder/phcoder' Serbinenko