The games can be copied to the hard drive from within the program, or by using a computer with image dumping software that outputs to a specific custom format.
Finally, there are intentional impediments introduced by some recent high-profile PS2 titles, such as God of War and Gran Turismo 4, to prevent them from being executed off the hard drive.
These include a fix to improve dual-layer support, one to implement a non-aligned data buffer (which allows Gradius V to be played from the HD), one to defeat newer copy-protection measures (popularly known as the God of War fix), one to support the new "slimline" SCPH-70000 series PlayStation 2 hardware and one to implement 48-bit Logical Block Addressing (which allows HD Loader to take full advantage of hard drives larger than 137 GB; or 128 GiB, as reported by HD Loader) as of 0.7c hard drives of up to 2 Terabytes can be used.
Version 0.8c continues support for 48-bit (up to 2 Terabyte hard drives), patches for Grand Theft Auto: Liberty City Stories, Grand Theft Auto: Vice City Stories and God of War II, 3 more modes and support for installing and running dual layer games directly off the hard drive.
Official HD Loader is extracted and released to the internet as a retaliation to the free library files used in its creation.
0.8c - A fix for the buffer alignment was added into the GUI Patcher app and made both GOW2 and GTA:LCS run without crashing.
However, this is not confirmed to work 100% across the board[citation needed] as certain PS2 models (mainly PAL 7xxx consoles) was reported to still freeze at splash screen; a currently-unfixable problem related to HD Loader version 0.8 or higher on PAL single-port network adapter models was the main problem[citation needed].
Open PS2 Loader, abbreviated as OPL, is an open-source program that allows playing of commercial games and homebrew installed from external storage devices.
It also has additional features, like the GSM feature that is used to disable videos and change the resolution of the game output, virtual memory cards (allowing the user to save on USB, HDD, SMB, i.LINK and MX4SIO), usage of the DualShock 3 controller over USB and Bluetooth (using a dongle) and a cheat engine.