Booting Macbook with refit and grub fails for USB-Stick

[kami22]

Hi,

i just installed Gentoo on my Macbook Air with dual Boot of Lion and Gentoo. I used refit as the main bootloader. At the first time i got an old gptsync with an old MBR. I got the problem that my Grub on the linux Partition (not the MBR) was not loading. But after updating my gptsync to the new MBR my linux Grub starts fine without any problem. Before all of this i can start from any Linux-Live-USB stick. But after updating my gptsync to the new MBR, the USB-Stick is known by the refit menu but it is not running. if i select the USB-Stick in the refit menu the display is going black for a while and after this, my Grub from the Linux partition is running.

So here are the facts:
- The Linux-Live-USB Stick is working fine. It can be used as a bootable stick. And i know that it is working with my refit.
- Before the update of gptsync with this settings in the MBR:
Current MBR partition table
# A Start LBA End LBA Type
1 1 236978175 EE EFI Protective
my USB-Stick was booting and my Linux-Partition fails to load.
But both of them were shown in the refit menu selection.

- After updating my gptsync to this:
# A Start LBA End LBA Type
1 40 409639 EE EFI Protective
2 409640 195722135 AC Apple RAID
3 195722136 196991671 AB Mac OS X Boot
4 * 196993024 234932223 Linux

My Linux Partition is booting really fine, but my Live-USB-Stick is not working.
I can see both things in the refit selection menu. If i try to make a chainloading with Grub it cant find the USB-Stick?

So maybe there is something wrong?

I also trying to chainload the USB Stick with Grub from my Linux Partition. I added this to the grub.cfg:

title USB-Stick
root (hd1)
chainloading +1

and this to the device.map:

(hd1) /dev/sdb

I also tried both with the hd2 and /dev/sdc.
But it is not working.

Thanks a lot for help.

Cu kami

[ulenrich]

I don't know if your thread is a question or solution. (Where is the question?)

By the way refit is known to not boot from usb-disks. The author has done some initial work for that but didn't succeed. You could try to use grub2-efi for that (I would like to here your experience of that). If there is a problem with gptsync of the hybrid MBR (gpt has no mbr if not hybrid), I would suggest to use sys-apps/gptfdisk

[kami22]

Hi,

thanks a lot for the answer.

Yes it is a question. I want to know, how i can boot from a USB-Stick with my Macbook. Because before i updated my MBR i can boot the USB-Stick, after the Update it is not possible. Maybe you can help me.

Thanks a lot.

Cu kami