Jan 302015

In some specific situations, you may want to backup only one partition but still wish to boot it as a disk image.
Lets see below how to turn a partition image into a disk image.

Before we start, have a a look at the below disk layout to have a better understanding of items such as MBR, BS, Disk and Partition.

1.Create a 1 MBytes (2048*512=1MB) header file (under virtualdisk, create raw disk image)
Note : instead of 2048 sectors, you can go for 63 or 128 or whatever « sectors before » may suit you – just report that number in the following steps.

2.Append this header to your partition image using the dos command line copy /b header.img+part.img disk.img

3.Adapt MBR type=07 (for ntfs), boot=80, chs start & end=1023*254*63, sectors before=2048, sectors=bootsector.totalsec+1
(You need to untick « hide advanced menu » under tools menu to enable advanced screens in CloneDisk).

4.Inject boot code (nt6) (this will also fix the mbr magic byte AA55).

5.Adapt bootSector hiddensec=2048 so that it matches MBR sectors before field

You are now ready to boot this image as it has all it requires to boot :
-a disk boot record
-a partition table
-a boot sector
-a consistent BPB (bios parameter block)

 Posted by at 19 h 05 min
Jan 242015

Lets start with a definition of the MBR :
A Master Boot Record (MBR) is a special type of boot sector at the very beginning of partitioned computer
mass storage devices. The MBR holds the information on how the logical partitions, containing file
systems, are organized on that medium.
Besides that, the MBR contains executable code to function as an operating system-independent chain boot loader in conjunction with each partition’s Volume Boot Record.

To make simpler, if a disk is a book, the mbr is the index table to quickly jump to each partitions.
MBR and GPT are just 2 different ways of writing that index (GPT handles a higher number of partitions and also bigger partitions).

So how to convert a GPT disk to MBR?

1.Write down the offset and length of your partition(s)

2.Delete the disk layout (this will not delete any datas, « only » the partition table and boot loader if any)

3.Create Disk (MBR style)

4.Create partition(s) with correct offset (most important) and length. Note that you can always correct these later by editing the MBR (advanced tools).
Choose IFS for a NTFS filesystem, or FAT32.

You end up with a MBR disk with a partition table similar to the GPT you previously had.
Note that you may want to inject a boot loader (nt6, g4d, etc) if this disk is a boot system one.
Also, this operation works the other way : MBR to GPT.

 Posted by at 19 h 20 min