I dug up my old GC Action Replay to use with a GC game on my Wii, and apparently it's too old to be compatible with the new Wii Menu software. I was going to purchase one of the newer GC AR packages, "guaranteed" to be compatible with the latest Wii software, but all the buzz I've read about it says that while it CAN be run on a Wii, users can't add or edit codes. Does anyone know otherwise?

I'm afraid it's been like that for a long time. They removed the option to add codes many many generations ago, long before they started making ones that work on the Wii. I can't really think of any advice to give...

p.s. The only reason your one doesn't work is because Nintendo's blacklisted it. If you have the HBC there's probably some way of letting it run.

Yeah, mine's the first generation GC Action Replay. The one that was meant to be used with the GC Keyboard for "easier code entry" and stuff. I hadn't realized the editing option was removed so early. They probably did it so people would buy the newer devices as they were released, or "update discs" or something. I mean, what's the point in buying a newer device if you could just find new codes and enter them yourself?

I think a contributing factor is the code that allowed homebrew without a modchip. You also needed an SD to GC memory card adaptor. The code redirected the gamecube to run a menu you'd placed on your specially formatted SD card. This let you boot any binary you wanted (from the SD card).
Don't think Datel removed this in the interests of protecting the GameCube's security though, they removed it because they wanted to be able to make more money.

That's kinda what I said.

Yeah, I was just elaborating. It wasn't so they could sell more Action Replays, it was so they could sell two products.