I am trying to create a multiboot USB drive with grub4dos. I started with a working bootable WinPE-like USB drive, based on Windows 7.

I modified the drive MBR with grubinst.exe (hd1), copied in its root grldr and the menu menu.lst file:

color blue/green yellow/red white/magenta white/magenta
timeout 30
default 0

title Win 7 test
rootnoverify (hd0, 0)
chainloader /bootmgr

I get the error:

Try (hd0, 0). This partition is ntfs but with unknown boot record
Try (hd0, 1) ...
...
Cannot find GRLDR.

If I hit a key, anyway it boots Windows 7. I would like to drop to the GRUB command shell, but when I hit "c" Grub boots into Windows.