Lock files on LiveUSB

Question

This is kind of two questions in one. I have Hirens on my 2GB flash drive. Somehow, while tweaking and adding files to the list, I killed the bootability. I had used unetbootin to create the usb. So...

Question 1: Without re-formatting and recreating the USB, is there a way to patch the bootloader so it becomes bootable again? I googled, but didn't quite find anything specific enough.

Question 2: Is there a way to lock the necessary files to prevent this from happening again?

I'm on Mac btw, so if I don't have to boot into VMWare, I'll be even happier.

Answer 1

I don't think there's any way to lock the files on an ordinary thumbdrive (you might be able to use a CDFS partition to lock the files in Windows, but this won't work for other OSes), though there are specialized thumbdrives that can provide hardware-based write-protection for specified files/directories.

However, to make it bootable again, you just need to make sure: 1.) there's a valid MBR, 2.) the bootable flag for the OS partition is set in the MBR 3.) a bootloader like SYSLINUX is installed.

I dunno if OS X has an equivalent to linux's install-mbr from the mbr package (apt-get install mbr), but you can always use fdisk to recreate the MBR and set the boot flag.