I want to mod my xbox360 and have read all the guides but would like to clarify a few things before i start.

i have a TS-H943A drive with the MS25 firmware and is this the correct way to change the firmware.

1) use "Xtreme Boot Maker" to create a custom USB booter, this will automatically edit the MTKflash tool for me yes ?

2)turn on PC and hook up the 360, once this is done type "SAMREAD SERIALNUMBER" and select my SATA chipset. (VIA 8237)

3)once it has created a backup of my original, restart all and type "SAMHACK SERIALNUMBER" and select my SATA chipset, it will then proceed and install the new hacked FW (Xtreme 4.2)

i should now have a hacked firmware installed ready to play my backups yes ?

also what is the diffrence between firmwares Xtreme 4.2A and Xtreme 4.2B ?

to create backups do i simply hook up my drive to the the PC again and use Xbox Backup Creator to create a complete rip and then burn with the same program, i should then be able to play the game yes ?

Yes, that is correct. After running Samread, you may want to boot into Windows or at least take the USB stick to another computer and open up your orig.bin (and hacked.bin) with 360 Firmware Toolbox to verify that it was a good read. Then, power off the 360, reboot the PC, power up the 360 at DOS, and run Samhack.

In order to backup games, you will have to use the 0800 disc burned to a DVD+R DL. Once in 0800 mode, the drive will be seen in Windows and you can use Xbox Backup Creator to backup the games.

Also, just make sure that you have both the power and video cables plugged into the 360, and ground the PC to the 360.