I can understand your frustration. As you’ll see by my signature I’m running a similar set-up and the instructions at the wiki did work – at one time. But I now find any attempt to download from http://ipkg.nslu2…. generates the “invalid magic” error. Originally, the link was http://ipkg-us-dyoung.nslu2… but that’s changed since I installed. So now, any of the files I attempt to download using ipkg install or manually generates the error.
I don’t think it’s really related to firefly. I don’t know if the solution is for Ron to host some of these packages as they are required for ff but until something changes a lot of users are going to run into this – just read the number of posts of members running into this.