This listing is for a Mars Pro GM-806HD for the PS2.

These chips are clones of the DMS4 lite chips. 

Unfortunately they're not perfect though, Settings can not be saved in the TOXIC menu. Also support on Fat revisions seems to be spotty. So far these have been tested in a V9 and a V10, in both situations they played region free discs and backups but none of bios commands worked. I've installed these in a few slims and they functioned perfectly fine. 

Holding the following buttons on boot will have the following results

Triangle - Boots to BOOT/BOOT.ELF on the memory card

Square - Toxic Menu

L1 - Disable Modchip

If booting a Ps1 or DVD movie you need to press reset twice to toggle to Ps1 mode. 

Single reset for Ps2 discs.

Here's the information about this chip from an archive of the original game-chip site

https://web.archive.org/web/20080118113628/http://www.game-chip.com/GM-806HD-1.htm