Hi, at the risk of reopening a mild flame (excuse please, I'm newbie) I've had similar trouble with my China made S5. Yes, I did read all the CHDK links, I did determine the firmware version (same as the originator's: P-ID: 3148 NT D, Firmware ver 1.01 B, No error, June 14, 2007 20:11:19. Did pick the zip file appropriate to 101b. I am using a Sandisk Ultra II 2.0 Gig card that is brand new. Made the card bootable.
Differences are that my camera does start up with this card in place, does show the splash screen, does show the battery data, does show the time and op: 22 in the upper right corner of the screen. But: no button (I've tried them all) turns on the ALT function. The camera works fine, but the screens are the native ones; the pictures look fine, but no different than if I'd never installed CHDK.
Would appreciate any advice. Thanks to all.