Actually that's incorrect, I can force it to boot by holding down the forced boot combination A + B + X + Y present in FlashMe with my MK3 inserted and it works just fine.
He has a MK1 not MK3, and MK1 not FlashMe - you still need a game in the MK to boot to the NDS FlashMe app before you have access to the key combo... if one already had installed and understood FlashMe's use, they would not be concerned with using the MK1 any longer, for the most part. And another though, MK is build using different logic/processor chips than MK3 - asic vs cpld - which also makes a big difference in the way the circuit operates.
Got my Neo-Max 1G in today, and am in the process of writing the review, hopefully it will clear up some of questions

I know I had a couple very pleasant surprises when I checked out the disk

tehxan: I had to take a couple days away, so I did not get to your question very quickly...
Did you try the steps in the faq for basic use, to see if the homebrew I linked there and tested with those steps would work for you?
I have been told MK4 with compatibility to new firmwares is a
possibility in the future, but I dont think they are planning on making such a device just yet. Dont count on it being around soon in other words.
So far as I can tell, the only way to make a newer firmware DS compatible with MK* (magic key x not mario kart) is to use flashme first - and on new DS firmwares the only way currently to do that is to get a "PassMe2" programmed for a specific game you already have, and use the SRAM file for that game so the PassMe2 has code to boot to.