I recently softmodded my bro's 4.2u wii using a guide on another website.

I was able to play soul calibur 2, p.n.03 and fire blade - all 3 discs are original pal gamecube games, not backups.
I started the games via disc channel.

HOWEVER when I tried to play my fourth gamecube game(zelda twilight princess), also a pal original disc for the gamecube, the game is recognised as a gamecube one in disc channel and when i press start the wii seems to start loading it but the screen remains blank and nothing happens.

This odd behavior only occurs with zelda twilight princess, and since I have no other gamecube discs that makes a 3/4 success rate :|

I had enabled "region free everything" system hack in priiloader - reason for the 3 games working fine on a ntsc wii.

Then I did something different- disabled the region free everything system hack in priiloader and tried neogamma to boot the soul calibur 2 game. This worked! BUT when I tried the zelda disc the same blank screen was the result.

Next I tried usb loader gx, having a wbfs usb flash drive. I inserted the soul calibur 2 disc, usb loader gx asked if i wanted to mount it and i said yes and it detected the disc as soulcalibur2 and the game started fine!
I did the same for the zelda game, usb loader gx detected the disc as legend of zelda: twilight princess etc and when i clicked on it to load, SAME BLANK SCREEN!!!

summary of facts:
gameriginal pal zelda twilight princess for the gamecube
wii: softmodded 4.2u using mentioned guide^
other stuff: this zelda game works on a gamecube console, it also works on a pal wii (2 separate wiis i have used in the past)

ANY ideas what the problem might be?

more thoughts/info on the matter:

Warning: Spoilers inside!

1. HBC 1.0.8 IOS58 v24.31 / Priiloader v0.4 (r78) IOS v70 sm v481

Neogamma R8, ISO249 (Rev17)

+Region options
-Boot lang (console default, auto force, etc)
-force video (wii, disc, NTSC480i/p, (M)pal480i/p, pal576i)
-patch video (no, normal, more, all)
-vidtv patch (y/n)
-patch country st. (y/n)

+config options
-hook type (none, vbi, kpad, joypad, gxdraw, gxflush, ossleepthread, axnextframe)
-ocarina on (y/n)
-debugger (y/n, p. start)
-altern. dol (disc+ only, n/, storage, disc, disc+)
-search patches (y/n)
-storage device (sd/usb using cIOS/IOS36/IOS61)
-gamecube mode (MIOS, int, ext)
-save config (y/n)

+rebooter mode
-recovery mode (y/n)
-region free (y/n)
-remove copy flag (y/n)
-button skip (y/n)
-skip updates (y/n)
-force CIOS (y/n)
-preloader support (y/n)

i tried forcing the pal video but was unable to get the game to run.
Above are the settings for neogamma to be clear what is configured
Is it possible that i am missing some files that are required to run some pal gamecube games on a ntsc wii?

came across this in another thread on another website:

"sometimes the updates install new IOS's, so you will still have to manually install IOS's if a game requires a certain IOS that you do not have installed, you will get a black screen if you do not have the required IOS."
so im thinking maybe im missing an IOS that is required by twilight princess :s

2. sysCheck v2.0 by Double_A
...runs on IOS58 (rev 6175).

Region: NTSC-U
System Menu 4.2 (v481)
Hollywood v0x21

Boot2 v4

Found 68 titles.
Found 41 IOS on this console. 6 of them are stub.

IOS3 (rev 65280): Stub
IOS4 (rev 65280): Stub
IOS9 (rev 778): No Patches
IOS10 (rev 768): Stub
IOS11 (rev 256): Stub
IOS12 (rev 269): No Patches
IOS13 (rev 273): No Patches
IOS14 (rev 520): No Patches
IOS15 (rev 523): No Patches
IOS16 (rev 54321): Trucha Bug, ES Identify, Flash Access, NAND Access
IOS17 (rev 775): No Patches
IOS20 (rev 256): Stub
IOS21 (rev 782): No Patches
IOS22 (rev 1037): No Patches
IOS28 (rev 1550): No Patches
IOS30 (rev 54321): Trucha Bug
IOS31 (rev 3349): No Patches
IOS33 (rev 3091): No Patches
IOS34 (rev 3348): No Patches
IOS35 (rev 3349): No Patches
IOS36 (rev 54321): Trucha Bug, ES Identify, NAND Access
IOS37 (rev 3869): No Patches
IOS38 (rev 3867): No Patches
IOS50 (rev 54321): Trucha Bug
IOS51 (rev 4864): Stub
IOS53 (rev 5406): No Patches
IOS55 (rev 5406): No Patches
IOS56 (rev 5405): No Patches
IOS57 (rev 5661): No Patches
IOS58 (rev 6175): No Patches
IOS60 (rev 54321): Trucha Bug
IOS61 (rev 5661): No Patches
IOS70 (rev 54321): Trucha Bug
IOS80 (rev 54321): Trucha Bug
IOS202 (rev 65535): Trucha Bug, NAND Access, USB 2.0
IOS222 (rev 4): Trucha Bug, ES Identify, NAND Access, USB 2.0
IOS223 (rev 4): Trucha Bug, ES Identify, NAND Access, USB 2.0
IOS236 (rev 54321): Trucha Bug, ES Identify, NAND Access
IOS249 (rev 17): Trucha Bug, ES Identify, NAND Access, USB 2.0
IOS250 (rev 65535): Trucha Bug, NAND Access, USB 2.0
IOS254 (rev 65281): BootMii
BC v6
MIOS v10

Report generated on 2010/09/06.