Grub Bootloader authentication

Hi

I am a newbie. I am trying to get MBR shadow working. I have 2 physical memories in my system. i.e. I have the MBR/grub with password enabled on flash 1(read only) and the other flash memory will have it's own MBR and corresponding OS(say windows).

I want to boot grub, enter password and then have it jump to the MBR on the second flash. However, if the OS on the second flash reboots(soft reset with no power loss), I want it to go through grub again(residing on flash 1). How do I achieve this?

I think if you set the boot order in bios it will boot from flash drive 1 if it is plugged in.
If you want to disable boot from flash drive 2 then zero the MBR bootloader code ... it will not prevent someone from booting from flash drive 2 but will stop them doing it by just removing flash drive 1. You could create a small partition on flash drive 2 and install grub with config files and password ... but again this does not completely prevent someone booting the OS on flash drive 2.