Boot0: GPT Huh? and Can't boot without USB

[rwillett]

The AMD cards have a known issue that require you to hijack the EFI partition and install boot stuff in there. This is known as the EFI mod.

If you are booting from an internal graphics card, then you do not need the EFI modification. So when you say that it works with the internal card therefore there must be a problem with the AMD card, you are correct, there is a problem with the AMD card, however this is a known issue and a workaround, the EFI mod, is the known and accepted solution. Now you may have a hardware fault (I'm choosing my words carefully) with the AMD 270X card you have, or it may be that there was an issue with the install and that the consequences of that installation issue manifest itself so that it appears that there is a hardware fault with the AMD card.

Sadly too many people assume that there is a hardware fault when it turns out to be an issue with the installation, somebody has typed the wrong command in, pressed return at the wrong time, the BIOS is wrong. There are so many ways to screw up, it sometimes amazes me these things ever work.

However I can speak from personal experience having built (sadly too many times), a number of machines with AMD 5770 cards, AMD 7970 cards and AMD 280X cards in both genuine Mac Pro's (though old ones) and Hack's that the AMD cards do work very well with very little work needs to get them going. As an example the 5770 required no boot flags, the 7970 required no boot flags and my current dual 280X system required, you guessed it, no boot flags, no drivers but the EFI mod to make them work.

The AMD cards are good cards, they may not be the best for gaming or playing BF4 but Mac OS X sings with them.

My suggestion would be to install with the internal graphics card only. Get that working and then put the 270X card in and then apply the EFI mod. You may have too many things going on and life is getting too 'interesting'. Its not an issue to install Yosemite and then put the graphics cards in afterwards. If you can then boot from the USB key and you have the graphics card recognised then you know that all you need to do is to do the EFI mod and you're good to go.

Rob

 

[fernandR]

Rob, thank you. I will follow your advice when I'm building a machine with an AMD card. BUT I AM NOT. That's what I've been talking blue in the face about.

So I can't try the EFI mod. Because as I keep saying it was freezing, looked like a PowerSupply glitching, and I sent it back.

I gather you like AMD cards, and I hear you're saying that you've found the EFI mod does the job. Fantastic. Since you like these cards and know how to make them work, can you tell me what the Boot0: problem actually consists of, and how moving the boot stuff to the EFI partition solves the issue?

 

[rwillett]

Here's your original quote.

I have an i7-4790K ASROCK Z97 Anniversary NV 970-4GB system working fine with 10.10.3. So I made a SuperDupe of the SSD boot drive and put it in a new i7-4790K box with the same MB, just the video card is different, a Dataland R9 270X -2GB. I could not get the system to boot, BIOS would say no boot system found. I could always boot by starting with the Unibeast USB stick, then selecting the SSD. So I updated the MB BIOS to 1.50 (the working box has 1.40). Now I get the enclosed screen shot when it fails to boot with no USB stick. I have been booting with the USB stick and re-running Multibeast, trying different things, but I'm shooting in the dark as I don't understand the boot sequence. I can't add any boot flags when not booting because the Boot0: message occurs before any mac/hack screens. Booting with the USB stick, it runs OK, the video is identified as AMD Radeon HD 7xxx. Anyone know what this boot0: message means? Any remedies? THANK YOU.View attachment 135454

and another post

Warm thanks for your help, Jithin, but I gave up on this machine as it froze on me a couple of times that evening. Given the AMD R9 270X problems, no time for this, it's now on its way back to Newegg. And it's the last time I buy a PC with an AMD card.

and

This is my second iBuyPower i7 system this month, and while the first was a open box, not much wrong with it (iBuyPower is replacing the radiator and front door) and a great deal, with a SSD and a 4gb NV 970 (I'm typing on it now), the second one seems like it's got (at least) a power supply problem. Since now I know the AMD is a troublesome dog anyway, it's going back.

and

Thanks, Jithin! Not sure how best to proceed. The problem is the AMD R9 270x card. If I move the SSD to the "identical" system with the NV 970, it boots and works just fine. In the system with the AMD R9 270x I can only boot with the integrated graphics (or a USB stick).

Whilst you may have meant to say that your were not using the 270X card, the way I read this is that you had issues with it. I have no idea what an iBuyPower i7 system is. My assumption is that it was a computer with a i7 chip in. You mention, at least to me tangentially, that you have a power supply problem. You also mention an EFI change

Thanks for your help. I may try to complete the EFI move tomorrow just to see and report here, before I pack it up. But it sounds like MBR might be a solution.

Doing an EFI mod is normally associated with using an AMD card. So forgive us if we misread your e-mails and assumed you had an issue with a 270x card. I have just reread the entire chain to check what I have written, Jithin has written and you have written and it still reads to me like a 270X issue. Hence my comments on EFI mod etc etc etc.

The boot0 issue is described here:
http://www.tonymacx86.com/general-help/65706-boot0-error-official-guide.html

It appears to be caused by large (4K) blocks on large (> 1TB) disks used for booting. I have never booted from anything other than a 512GB SSD, though have used 3TB and 4TB disks for backup purposes.

I think the issue is caused by confusion over the 270X card AND the issues caused by booting with AMD cards which gives a GPT issue error (which looks a bit like boot0).

Rob

 

[Jithin.C.V]

First follow this guide : http://www.tonymacx86.com/general-help/115818-install-bootloader-extra-efi-partition.html

If the boot0 error showing after following the above guide then follow this : http://www.tonymacx86.com/general-help/65706-boot0-error-official-guide.html


Note:- You can avoid all these problems with the usage of CLOVER boot loader.

 

[fernandR]

Thanks, Guys. Because the machine was freezing I sent it back before I could try correcting the AMD Boot0: I said I might try the EFI mod, but in the end I gave up.

iBuyPower.com and CyberPower.com are American companies that assemble systems - at a fair price. Newegg sells 'em, sometimes at a fantastic discount. Their power supplies are the achilles heel, and although it's replaceable at low cost, this time I didn't have a replacement on hand and I just sent the box back.

So I couldn't do the EFI mod or try the MBR approach. But I will be reading up on the Boot0: .

At this point I'm rebuilding my i5 system and will be upgrading it to Yosemite.

My i7 is running 10.10.3 OK. I just removed the USB kext since it's no longer necessary, and that seems to have improved USB handling. But it still sometimes returns from sleep with a black screen.

Thanks again.

 

[rwillett]

Do a Clover install without any external Graphics card. The Asrock 97 MB's are pretty good from what I hear though I have Gigabyte.

Once thats working and stable, add a graphics card of which ever flavour.

Start slowly, work methodically through the install and check.

Only complicate things at the end and do ONE thing at a time.

Rob

 

[fernandR]

So if I want to start over, where/how do I get the current OsX 10.10.3 installer?

 

[Jithin.C.V]

So if I want to start over, where/how do I get the current OsX 10.10.3 installer?

Only from App Store.....