Arch Linux

jwhendy

Member

Registered: 2010-04-01

Posts: 621

Chainload win7 from backup of its encrypted bootloader with syslinux

Long story very short:
- I have Arch and Windows 7 on the same SSD, separate partitions
- I can't seem to use EasyBCD as I used to in order to boot Arch using the Windows bootloader, which I believe is due to an updated version of McAfee*
- I can only have one bootable partition flagged (currently the win7 system partition), and thus my workaround has been to press Esc and then F9 during boot to point to a flash drive containing syslinux which can boot my Arch partition

I was reading around and there seems to be a way I might bypass this by chainloading a backup of the encrypted McAfee mbr. It's old, but this McAfee forum post suggests it's possible.

3. Boot with a linux live CD and copy the MBR
                    dd if=/dev/sda of=/your_usb_drive/safeboot.mbr bs=512 count=1

4. Install linux, GRUB will overwrite the MBR

5. Boot into linux, copy safeboot.mbr to /boot

6. Update /boot/menu.lst as follows:
title Microsoft Windows XP
  rootnoverify (hd0,0)
  makeactive
  chainloader (hd0,5)/safeboot.mbr

Modify (hd0,0) to match your windows partition, (hd0,5) will be your /boot partition.
Remember that GRUB numbers partitions starting with 0 - (hd0,5) is /dev/sda6

What's the equivalent of this for syslinux? From perusing the docs, I was thinking something like this?

LABEL windows
         MENU LABEL Windows
         COM32 chain.c32 file=../mbr.bin  ## where mbr.bin is the dd of the current McAfee bootloader on /dev/sda, saved to /boot/mbr.bin on my boot partition
         APPEND hd0 1

I'm just doing a sanity check, as I haven't gotten it to work yet, but think since I have a secondary hard drive and a bootable USB in the computer, perhaps I just haven't figured out which "hdx y" combination I need yet. If anyone has done this, confirmation or correction would be greatly appreciated!

* Not positive, but I've had odd experiences ever since trying to recreate my former setup on a newly issued work computer. My old one had version 6.x and this method worked fine. The new laptop is on 7.x, and I've encountered several issues that I now believe are all related to McAfee Endpoint Encryption (EEPC), which is a relief, as I thought I was going insane:
- non-system partitions formatted by one OS cannot be opened ny the other
- the type/contents of the partition not agreed upon even by 3rd party win7 partition software; similar post on the partition software forums
- EasyBCD not working how it used to, ]similar post made on EasyBCD forums