HP t620: Firmware 





On power up the F10 key will get you into the BIOS which has an American Megatrends Inc copyright message. At the top of the screen it's identified as the Hewlett-Packard Setup Utility. The 'System Information' screen identifies it as BIOS Revision L40 v02.08 dated 10/09/2014.

Under Storage->Boot Order it displays a screen listing:

▶UEFI Boot Sources USB Floppy/CD USB Hard Drive Legacy Boot Sources USB Floppy/CD Hard Drive SanDisk Cruzer Blade 1.26 SATA1 Network Controller 1 (Realtek PXE B02 D00)

With the example above I had a 4GB SanDisk Cruzer pen drive plugged into one of the USB ports. You hit enter to select a particular device and use the up/down arrow keys to position it in the hierarchy.

There is a 'Security' screen that lets you enable/disable a lot of things. For example you can individually enable/disable the eight USB ports. In fact there is a lot you can play with in the BIOS settings.

BIOS Password Reset

t620 jumpers

In the corner of the board by the Wireless Card there are a number of Jumpers on a header. The silk screen markings identifying their purpose are a little displaced due to the closeness of mPCIe connector. We have BBR (E15), BB (E14), PSWD (E49) and FDO (E1). There should be a link on E49.

To reset the BIOS password it is a simple matter of:

  • Ensure the t620 is powered off.
  • Remove jumper E49
  • Power up.
  • Wait long enough for the BIOS to initialise everything and start looking for something to boot.
  • Power down.
  • Replace jumper E49.

When you next power up the BIOS password should have been cleared.

Note: This feature can be disabled in the BIOS. Under the Security tab, if you have a password set, you can set the password options to Stringent Password which does this. The HP documentation does note:

When enabling Stringent Password, losing the passwords may render the system permanently unusable.

Other links

From a quick Google the other links mentioned above are:

  • Flash Descriptor Override.
  • Boot Block
  • Boot Block Recovery

The last two are something to do with 'Crisis Recovery'. I haven't researched this area and currently have nothing to add other than the words above.

BIOS Update

At one point in my testing I was getting some odd issues that I thought might be BIOS related. There is an updated BIOS available on the HP website that takes you to L40 v02.14 10/20/2016. It's in the file sp78303.exe[*]. There aren't any blow-by-blow instructions for applying it, and I did go round in circles a bit to start off with. Here's my suggestion of a way to do it on my Windows 7 equipped t620.

  1. Download sp78303.exe from HP's website.
  2. Copy it onto a pen drive. (I used a 1GB drive).
  3. Boot into Windows 7 on the t620.
  4. Hold down the shift key and log off.
  5. Logon as Administrator (password: Administrator).
  6. Insert the pen drive.
  7. Open up file explorer (WindowsKey + E).
  8. Navigate to D:sp78303.exe and double click on it to run it.
  9. I changed the suggested path to D: for the extracted files.
  10. On the next screen select "Update the BIOS on this device."
  11. Leave the pen drive in place and let the software do it's thing.
  12. It should reboot and then start programming/verifying the BIOS.
  13. After the next reboot you can remove the pen drive

I subsequently spotted a BIOS menu item under 'Security'. This is 'Tool-less BIOS Update' and requires you to enter a 'BIOS Image File Name' which I assume must be on a pen drive?

* [July 2019] Sean drew my attention to the fact that the latest version of the BIOS available for download from the HP website is L40 00.02.19 Rev.A Mar 5, 2019 which is in the file sp95251.exe.

In September 2020 I heard from Jan. He had just bought a t620 with an ancient BIOS. Being an early BIOS it didn't include the option to flash a new BIOS. Also, as is often the case, the seller had wiped the flash drive so there was no native OS to allow him to run the HP Windows tool. He also had problems trying to get the HP Linux tool to run....

It turns out that many HP desktop PCs (including the t620) have an inbuilt BIOS recovery mechanism. (see

There are two parts to this - first one must create a Recovery USB flash drive using the tool HP includes in the BIOS download for Windows (Win\L40_0219.exe).

Next, one needs to power off the terminal, plug in the flash drive, hold down the Windows key and the 'B' key, then press the Power button for 3 seconds. After you release the power button the power LED will start flashing red. You need to continue to hold down the Windows and 'B' keys until you hear a sequence of beeps or the BIOS update screen appears. This takes about a minute.

The same procedure should apply to t520 as well.

USB oddity

There was an interesting(?) thing I noticed as I was trying things out (and upgrading the BIOS) under the native WES7. One of those little Windows 'balloon' messages appeared when I plugged a pen drive into the top port on the front of the t620. It read:

"This USB device can perform faster if you connect it to a Hi-Speed USB 2.0 port."


Missing Memory

Having found a memory issue with the HP t610 I decided to check out the t620 and found exactly the same problem.

In the BIOS there is a setting:

Advanced -> Device Options -> Integrated Graphics

where you can set the size of the Video RAM memory.

You use the left or right arrow key to switch Integrated Graphics between Auto or Force.

According to a HP manual all Auto does is set the buffer size to 256MB if you have 4GB of RAM fitted, and to 128MB if you have 2GB of RAM fitted.

The Force option adds a new parameter that lets you explicitly set the UMA Frame buffer size. This can be set to one of 32M/64M/128M/256M/512M/1G.

On a t620 fitted with 4GB of RAM I ran TinyCore Linux a number of times with different settings for the UMA Frame Buffer size. In each case I looked in the boot log to see what value was reported for available memory.

Memory: 2527384K/2566392K available (5401K kernel code, 419K rwdata, 1380K rodata.....

The results are in the table below and are similar to those I found with the t610:

Buffer size  Free memory
Auto (256MB)2566392K

With a Video buffer size set 64MB or 128MB you get the expected ~3.5GB of RAM. Set it to 256MB and you lose a lot more RAM than you would expect. As you can see from the figures above:

  • Moving from 64MB to 128MB you lose another 64MB of RAM. (Makes sense)
  • Moving from 128MB to 256MB you lose another 650MB of RAM (Makes no sense)

Anyone have an explanation for this?

My t620 is also running WES7 so I thought I'd check what it reported using the HP System Info utility

With the Video Buffer set to 64MB

Installed Physical Memory (RAM) : 4.00GB
Total Physical Memory           : 3.38GB
Available Physical Memory       : 2.69GB

With the Video Buffer set to Auto (sets the buffer size to 256MB):

Installed Physical Memory (RAM) : 4.00GB
Total Physical Memory           : 2.45GB
Available Physical Memory       : 1.76GB


Any comments? email me. Added April 2017    Last update December 2019