Remove Host Protected Area (HPA) feature -

Remove Host Protected Area (HPA) feature

by Adalbert Prokop ( on 2008

Warning! Manipulating the hard drive's internals is a serious action. It can destroy all data on your disk or even render it unusable. You should at least create a complete backup of your data. This description has been created to the best of my knowledge but I will take no responsibility for any damage or injury you may have done to anything or anybody after reading this description.


The abbreviation HPA stands for Host Protected Area. The area in question is a reserved space on the hard drive, to which the host has no access. The question remains open if it's resonable thing. The fact remains, that the hard drive is reporting less space to the computer as there effectivly is.

One problem emerged from the improper usage of this feature. I upgraded an Acer Travelmate 8000 with a 250 GB hard drive. Originally this laptop had only a 60 GB drive and the user's manual tells the maximal capacity is limited to 120 GB. After replacing the old hard drive with the new 250 GB one (WD2500BEVE) I saw that only approximately 137 GB are available.

The reason was detected quickly. The Travelmate's BIOS sets the available hard drive size to the previously mentioned 137 GB. The purpose of this behaviour remains in the dark, most probably it was intended to use the hidden space for backup or recovery information. But how to prevent it? The Travelmate's BIOS does not offer any control options for HPA.


The small toll HDAT2 written by Lubomir Cabla provides great assistance here. It's available as a Windows or DOS applications, alternatively also as a bootable CD image so one is not dependent on Windows or DOS. I've found this solution in a HDAT2 forum. You have to make the following changes to the harddrive.

  1. Set the space visibile to the host computer up to the harddrive's real capacity.
    This can be done by the menu option SET MAX (HPA) → NATIVE MAX ADDRESS [last sector] (in 48bit LBA mode).
  2. Prohibit the use of HPA for the harddrive, so that the Travelmate's BIOS cannot change the available space on next reboot.
    This options is available by the menu option Device Configuration Overlay Menu → Modify → Host Protected Area feature → REMOVE.

On the next reboot the harddrive is free of HPA support and the operating system can access the full harddrive's capacity.