#185 rEFIt won't boot USB anymore (used to work)

[Anonymous]

Hi,
Thanks for giving me an initial solution for installing Windows 7 on my new Mac Air from USB stick.

I have 2x USB sticks... One is a bootable USB stick with a Windows 7 installation image on it. I used this to install Windows initially, and I have successfully tested it again just now on another machine to make sure it's still bootable.
The other has rEFIt installed on it. I used this to boot the Windows 7 install before.

I now wish to load the Windows setup again but when I select the USB drive, it just boots me into Windows; no errors, no messages, just starts my Windows installation. Is this a known issue / is there a fix?

Cheers!
Daniel

[joevt]

To be clear:
1) You booted a Windows 7 installer on a USB stick connected to your MacBook Air and installed Windows 7 to your MacBook Air's hard drive.
2) You used rEFIt on a USB stick to boot the Windows 7 installation on your MacBook Air's hard drive.
3) You are attempting to use rEFIt (on your hard drive?) to boot the Windows 7 installer on the USB stick?

If 3 is true, but it doesn't work, it means that rEFIt does not know how to boot Windows from a USB stick. The rEFIt documentation states that USB devices are usually not supported by Apple's BIOS. But since it appears that you can get Windows to install from a USB stick on a MacBook Air, then it means that Apple's BIOS has been updated on the MacBook Air to support USB devices. Therefore, the problem lies with rEFIt, unless there's something special about your USB stick.

Bypass rEFIt by pressing the option key at startup to get into the Startup Manager.
http://support.apple.com/kb/HT1310

To help rEFIt development, you can try selecting the USB stick from the Startup Disk preferences panel in Mac OS X, then dumping the contents of NVRAM using the following command in Terminal.app:

nvram -p

The following command produces the same results in a more readable format:

ioreg -w 0 -n AppleEFINVRAM | sed -n -E "/^[ \|]+[ ]+(\".*)$/s//\1/p;"

Verify that the USB stick boots using the Startup Disk preferences panel.

[Anonymous]

I can see how the post might have been confusing; I'll try to list the facts...

I have not installed rEFIt on my hard drive.
I have partitioned the hard drive to have an OSX partition and a Windows partition.
Native dual booting is working fine (holding option to get to the built in boot manager).

I made a rEFIt USB stick to boot Windows *installation* from a (different, simultaneously plugged in) USB stick. This worked great (thanks!).

Both OS's work fine and I can access both by using either the built in boot manager or using my rEFIt USB stick if I choose.

The only thing that will no longer work is booting Windows *installtion* via rEFIt USB stick like I did in the first place to install Windows; not trying to run Windows off the USB stick itself, just the installation.
When I try to boot from the Windows installation USB stick, rEFIt just boots Windows from my hard disk.

[Anonymous]

Windows setup USB stick has never worked on it's own on my Mac (works on other non-Mac computers). It does not show in the native boot manager nor in the startup disk preferences panel

[joevt]

It's odd that you were able to get the USB stick to work with rEFIt on your MacBook Air the first time but not after Windows is installed to the hard drive. To repeat your result, you would need to remove Windows. You wouldn't actually have to delete Windows, just remove the Windows partition entry from the MBR. If that didn't work, then convert the hybrid MBR back to a normal GPT protected MBR. However, the Windows installer on the USB stick wouldn't be able to see the Windows partition. That would be ok only if you wanted to work with a new partition.

You could try cloning the Windows installer to a partition on your hard drive and then boot from that. That's super easy with Mac OS X Installer but I'm not sure about Windows.

[Nobody/Anonymous]

Is there any debug I can do to try get a solution? Would the NVRAM dump help?
I wasn't aware you can delete a partition entry from the MBR (and reverse it); sounds... errr, risky but I'm game if you can teach me how...

I now have a single USB stick, MBR, 2 partitions. One FAT32 partition, one OSX.
FAT32 partition contains Windows setup files (and has been made bootable, tested on another machine); the OSX partition contains rEFIt.
I can launch rEFIt using this USB stick, but again, if I select to boot Windows (setup) from USB, it just loads Windows off my HDD.

[Nobody/Anonymous]

Hi guys,
I have exactly the same issue. I have a late 2010 MBA with Snow Leopard in the first and Windows in the second partition. rEFIt installed on HDD. I tried EVERYTHING. Linux USB sticks, all sorts of windows, BartPE, Grub4Dos, the original Microsoft "make USB win7 install program". Every single one of these sticks boots fine on a regular PC (Lenovo) Laptop. On the MBA what happens is, rEFIt always sees the stick and offers an option to boot from it but when I do the grey screen appears for 5 sec (BIOS emulation starts) but then I suddenly just end up in my regular on-HDD Windows bootloader where I have two options, Win7 and Win7 with 4GB memory patch. It's weird that rEFIt seems to *try* to boot off the USB stick (which actually also blinks rapidly for a while) but then I always just end up in the regular already installed windows (which then also boots just normally, totally ignoring the presence of the USB).
The USB drive of course shows up IN windows as a drive letter.

After reading A LOT on different forums, googling for hours etc. I have seen people in Youtube videos do exactly what I'm trying to do! Unfortunately nobody mentions their rEFIt version, so I can't say right now from which version on booting the 2010 MBA from USB was broken :(
Please help! I really need to boot from USB drives every now and then.

Thanks!

[Anonymous]

Just to confirm with mine, I am unable to rerun windows setup from the same usb key, after installing windows.

This worked the first time but now just boots straight into Windows.

Have a 2010 Macbook Air 13"

[Anonymous]

One more addition,

Removed the Windows 7 partition (had to completely delete it, format solved nothing) and refit was able to boot off the USB key again.

So unfortunately this completely kills triple-boot setups (I guess theoretically you could install and image each OS, repartition the drive and reload the images but this is far from ideal). And I have no idea if this would work either.

Of note, the 2010 Macbook Air has a weird EFI setup (it won't boot windows off USB,and will not let you select it through startup disk preferences)

This is documented but no idea why they did this.

Running the latest version of refit (0.14)

[joevt]

I would try using fdisk or gdisk command line utilities to remove Windows from the MBR without deleting the WIndows partition or contents (leave it in the GPT).

gdisk can be downloaded from https://sourceforge.net/projects/gptfdisk/
Documentation is at http://www.rodsbooks.com/gdisk/
Read the notes about Hybrid MBR's

Documentation for fdisk and gdisk is also available as a man page:
man fdisk
man gdisk

The update MBR code option (-u) in fdisk actually just erases the MBR boot code. rEFIt will add it's own MBR boot code if you're trying to boot an MBR partition and the MBR boot code is empty.

[Nobody/Anonymous]

So we have to insure and keep the MBR code blank?

Any idea whats causing this?

[Anonymous]

Facts and Myths of rEFIt on MacBookAir:
Fact : With rEFIt you can "select" the USB and install Windows on MacBookAir
Fact: AFTER you have installed Windows on MacBookAir you can still see and "select" the USB at startup with rEFIt!
Myth: With rEFIt you can "select" the USB in order to re-install or repair Windows on MacBookAir
You cannot re-install or repair Windows since rEFIt fails to "boot" this time from the USB and unfortunately it "boots from the HD!