[syslinux] Custom MBR

Michael A mikearm77 at hotmail.com
Mon Dec 15 04:30:52 PST 2008


Hi Geert
 
I have somehow registered myself for these emails and would like to know how I can get out of it all. Your assistance in this matter would be much appreciated.
 
Mike> Date: Sun, 14 Dec 2008 10:32:33 +0100> From: stappers at stappers.nl> To: syslinux at zytor.com> Subject: Re: [syslinux] Custom MBR> > Op 20081213 om 15:48 schreef YYZ:> > Hi,> > > > I have a multi-boot setup with windows installed on the active primary> > partition. Now this partition is encrypted and the only way to boot> > windows is through a custom boot loader provided by the encryption> > software (which requires entering a pre-boot password to unlock the> > decryption key). Unfortunately, this boot loader is pretty lame (in terms> > of multi-boot capabilities) and is completely inflexible (in that, it must> > reside in mbr + unused sectors of track0 and cannot be relocated). However,> > it's first stage in the mbr can be backed up in a file and chainloaded (as> > long as subsequent stages in track0 are intact). Additionally, it won't> > boot windows unless this partition is active.> > > > Now I could boot other operating systems by adding entries to the boot.ini> > of the encrypted windows system but this way, I would be required to enter> > the password even though those other operating systems that I finally boot> > are not encrypted. Not only that, this leads to the decryption keys loaded> > in the memory even when I'm not running encrypted windows.> > > > Now I want to completely bypass this boot loader by overwriting its first> > stage in MBR with custom code (while keeping the windows partition active)> > to transfer control to syslinux installed in an available partition (which> > in my case is a logical drive). Once I'm in syslinux, I can easily start> > any operating system I want (even the encrypted windows by chainloading> > the original mbr that I backed up in a file).> > > > Now, I looked at the syslinux mbr source (the newer version) and it> > appears to already have the code to parse the extended partition tables.> > With little modification, it should be possible to make it do what I want.> > Unfortunately, though somewhat familiar with assembly language, I don't> > think it's something I can pull-off myself.> > > > That's the reason for my request to bundle such a custom mbr with> > syslinux - it could act as a first stage loader for an unconditional boot> > into syslinux. The users would be able to install this MBR into sector 0,> > set the correct byte to the # of partition where syslinux is installed> > (0,1,2,3 or primary 4 onwards for logical), and the MBR code would find,> > load and execute the corresponding boot sector. Once in syslinux, they> > can interactively decide which operating system they want to boot into.> > > > Of course users can use the traditional mbr based on the activation flag,> > if they don't want this functionality.> > > > Thanks!> > > To me it sounds like the wish of having multiple MBRs,> but that conflicts the rule of "there is only one master".> > For another MBR, Master Boot Record, use another bootdevice.> Such as floppy disk or USB memory stick.> > Write the MBR on that extra device with a bootloader _installer_> Don't do writing of MBR with bootloader.> (a bootloader is for bootloading, sure not for writing boot information)> > > Cheers> Geert Stappers> -- > Those who care about the discussion,> care about the discussion order,> they reply below the text.> > _______________________________________________> Syslinux mailing list> Submissions to Syslinux at zytor.com> Unsubscribe or set options at:> http://www.zytor.com/mailman/listinfo/syslinux> Please do not send private replies to mailing list traffic.> 
_________________________________________________________________
It's simple! Sell your car for just $40 at CarPoint.com.au
http://a.ninemsn.com.au/b.aspx?URL=http%3A%2F%2Fsecure%2Dau%2Eimrworldwide%2Ecom%2Fcgi%2Dbin%2Fa%2Fci%5F450304%2Fet%5F2%2Fcg%5F801459%2Fpi%5F1004813%2Fai%5F859641&_t=762955845&_r=tig_OCT07&_m=EXT


More information about the Syslinux mailing list