Compatibility
HD Loader is not 100% compatible with all PS2 games. Some incompatibilities exist because game software depends on certain peculiarities of the PS2 drive hardware. Additional incompatibilities arise from the use of dual-layer DVDs in some PS2 games, which are sometimes not parsed properly by HD Loader (incidentally, dual-layer games can only be installed from a PC but as of 0.8c it's possible to install them from HD Loader). Finally, there are intentional impediments introduced 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.
In response to the limitations of HD Loader, a number of independent programmers have developed patches which extend the functionality of HD Loader to improve game compatibility. 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.
These patches have been accumulated into unofficial HD Loader release known as 0.8b, The unofficial HD Loader is currently at version 0.8c as of April 2007. Version 0.8c continues support for 48bit (up to 2 Terabyte hard drives), patches for both GTA:LCS/GTA:VCS & GOW2, 3 more modes and support for installing and running dual layer games directly off the hard drive.
Some games need to be patched in order to be played with HD Loader. Another may require using tricks, such as starting the game with an older, digital controller and then switching to DualShock 2, or refuse to install. According to PS2HD.COM, the compatibility rate of patched HD Loader is around 88.2%.
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