I always used NTSC-U version of Gran Turismo 4 with OPL from internal HDD.
I now installed the PAL version (SCES_517.19), normal/complete rip from the DVD (MD5: 5b504676595dea8b32cb675993285fca).
The game immediately starts as the NTSC version but when the first screen fade out the screen remains black. The Ps2 is not freezed I can IGR/IGR-power-off.
Is this normal behavior, PAL version is supposed to not work from internal HDD? I cannot find any clear answer online, aside some claims that a cutted DVD-5 version of the game should work.
P.S. I made any possible tests with MODEs, different OPL versions from 0.9.2 onward, also tested on 2 different Ps2 (39004 and 50004), always exact same behavior.
I extracted back the ISO from the HDD for checking eventual corruption during installation but the MD5 is perfect.
Never experienced any problem with the NTSC-U version of the game (complete rip DVD-9).
I solved this way:
I thought to try the game with HDLoader. Since I installed it (as all other 131 games) with the new HDL Batchkit 1.1.5, HDLoader couldn't see the games. So I deleted GT4 and installed it again with HDL Dump Helper Gui (that put HDL. as prefix of installed games).
Very good, since this way HDLoader can only see GT4, so gamelist loads very fast. The game plays perfectly.
But some memories started to arise...
** So I tested the game with OPL again and it worked.
Game MD5 is the same either installing it with HDL dump helper gui 2.3 or newer HDL based programs. The differences I can see are the UDMA 4 flag newer programs add automatically and the games prefix that lacks HDL.
I don't know if also the fact to have HDLoader Settings partition and/or the HDL gamelist on the HDD can make some difference in OPL compatibility? I always had that impression.
I should try to install the game again with HDL Batchkit to figure out... But tomorrow my relative will come to pick everything up, also the HDD is very old.
For now I'll keep using HDL Dump Helper gui for installing Ps2 games.
**I remember some problems already happened to me years ago, the first time I used HDL dumx for installing Killzone on a 2TB HDD, there was stuttering and other problems on first startup. Then I deleted it and re-installed with HDL Dump Helper Gui.