Persistent USB
Contents |
Required Tools and Preparation
- USB Thumbdrive (Minimum 8GB, Recommended 16GB)
- Backtrack 5 ISO file, md5sum verified or a bootable BT5 DVD
- Vmware to boot the iso if you choose to perform all the steps from within a VM as I did
It makes no difference which way you choose, just be aware that drive designations may be different for you than they were for me.
This may not be the best way to do this, but it works. I am sure there is a more elegant way of doing this which I may revisit later if the need arises and time allows.
Partitioning
Display the available drives with the command below and determine which drive you wish to install to.
dmesg | egrep hd.\|sd.
The target drive needs to be partitioned as follows:
- The first partition needs to be a primary partition of no more than 3.5 GB and set to type vfat (I have made this partition larger than needed so as it covers all iso's and future versions). Make the partition active to avoid boot problems.
- The second Partition which stores the changes should take up the rest of the space on the thumbdrive, or as much as you wish to allocate for saving changes (4.5GB at an absolute minimum).
Run the following commands to perform the partitioning.
fdisk /dev/sdb# Use the Appropriate Drive Letter for Your System.
Delete any existing partitions
Command (m for help): d Partition number (1-4): 1
Create the first Partition
Command (m for help): n Command action e extended p primary partition (1-4) p Partition number (1-4): 1 First cylinder (1-522, default 1):Using default value 1 Last cylinder, +cylinders or +size{K,M,G} (1-522, default 522): +3500M
Create the Second Partition
Command (m for help): n Command action e extended p primary partition (1-4) p Partition number (1-4): 2 First cylinder (193-522, default 193):Using default value 193 Last cylinder, +cylinders or +size{K,M,G} (193-522, default 522): Using default value 522
Set the First Partition to vfat/fat32
Command (m for help): t Partition number (1-4): 1 Hex code (type L to list codes): b Changed system type of partition 1 to b (W95 FAT32)
Set the Second Partition to Linux
Command (m for help): t Partition number (1-4): 2 Hex code (type L to list codes): 83
Make the First Partition Active
Command (m for help): a Partition number (1-4): 1 Command (m for help): w
At this point you may need to eject and reinsert the drive for the partition table changes to be recognized and for you to be able to perform the rest of the steps.
Format the Partitions
mkfs.vfat -F 32 -n BT5 /dev/sdb1 mkfs.ext3 -b 4096 -L casper-rw /dev/sdb2
Please note that the second partition MUST be labeled as casper-rw exactly as written here, no other label will work, not even if you use caps instead.
Install BackTrack to the Thumbdrive
Mount the first partition which is sdb1 in this example.
mkdir /mnt/sdb1 mount /dev/sdb1 /mnt/sdb1
Copy the files from the iso to the USB drive
cd /mnt/sdb1 rsync -r /cdrom/* .
This last step will take a couple of minutes to finish, maybe more depending on the speed of your drives and method you are using.
Make The Drive Bootable
In this next steps, we make the Thumbdrive Bootable and copy files into their proper location with their correct names.
syslinux /dev/sdb1
This has made the drive bootable, but as we are using files from isolinux with syslinux they will be named incorrectly and be in the wrong locations. We can easily fix that with the following commands.
cp -r isolinux syslinux cp syslinux/isolinux.cfg syslinux/syslinux.cfg cp syslinux/isolinux.bin syslinux/syslinux.bin
Configure Persistence
To configure persistent modes in the entries we want, we need to do the following:
nano syslinux/syslinux.cfg
Our original syslinux.cfg will look like this:
default vesamenu.c32 prompt 0 timeout 300 menu title BackTrack Live CD menu background splash.png menu color title 1;37;44 #c0ffffff #00000000 std label DEFAULT menu label BackTrack Text - Default Boot Text Mode kernel /casper/vmlinuz append file=/cdrom/preseed/custom.seed boot=casper initrd=/casper/initrd.gz text splash vga=791-- label STEALTH menu label BackTrack Stealth - No Networking enabled kernel /casper/vmlinuz append file=/cdrom/preseed/custom.seed boot=casper initrd=/casper/initrds.gz text splash staticip vga=791-- label FORENSICS menu label BackTrack Forensics - No Drive or Swap Mount kernel /casper/vmlinuz append file=/cdrom/preseed/custom.seed boot=casper initrd=/casper/initrdf.gz text splash vga=791-- label NODRM menu label BackTrack noDRM - No DRM Drivers kernel /casper/vmlinuz append file=/cdrom/preseed/custom.seed boot=casper initrd=/casper/initrd.gz text splash nomodeset vga=791-- label debug menu label BackTrack Debug - Safe Mode kernel /casper/vmlinuz append file=/cdrom/preseed/custom.seed boot=casper initrd=/casper/initrd.gz text-- label memtest menu label BackTrack Memtest - Run memtest kernel /isolinux/memtest append - label hd menu label Hard Drive Boot - boot the first hard disk localboot 0x80 append -
In my case I just wanted to add a new Default boot which is exactly the same as the original default entry with the exception of being my new persistent mode.
To do the same you should make your syslinux.cfg look like the following:
default vesamenu.c32 prompt 0 timeout 300 menu title BackTrack Live CD menu background splash.png menu color title 1;37;44 #c0ffffff #00000000 std label DEFAULT menu label BackTrack Persistent Text - Persistent Text Mode Boot kernel /casper/vmlinuz append file=/cdrom/preseed/custom.seed boot=casper persistent initrd=/casper/initrd.gz text splash vga=791-- label text menu label BackTrack Text - Boot Text Mode kernel /casper/vmlinuz append file=/cdrom/preseed/custom.seed boot=casper initrd=/casper/initrd.gz text splash vga=791-- label STEALTH menu label BackTrack Stealth - No Networking enabled kernel /casper/vmlinuz append file=/cdrom/preseed/custom.seed boot=casper initrd=/casper/initrds.gz text splash staticip vga=791-- label FORENSICS menu label BackTrack Forensics - No Drive or Swap Mount kernel /casper/vmlinuz append file=/cdrom/preseed/custom.seed boot=casper initrd=/casper/initrdf.gz text splash vga=791-- label NODRM menu label BackTrack noDRM - No DRM Drivers kernel /casper/vmlinuz append file=/cdrom/preseed/custom.seed boot=casper initrd=/casper/initrd.gz text splash nomodeset vga=791-- label debug menu label BackTrack Debug - Safe Mode kernel /casper/vmlinuz append file=/cdrom/preseed/custom.seed boot=casper initrd=/casper/initrd.gz text-- label memtest menu label BackTrack Memtest - Run memtest kernel /isolinux/memtest append - label hd menu label Hard Drive Boot - boot the first hard disk localboot 0x80 append -
Now we need to test our new persistent mode.
Reboot your system from USB and select "BackTrack Persistent Text - Persistent Text Mode Boot" or wait for the timeout to boot it as default. To test the persistence, create a file anywhere on the system, but a new folder or text file on the Desktop is a very easy visual difference to check for.
Reboot.
If your file is there after a reboot, you have been successful.
