i had the same problem, and also got a free replacement because yes Oliver is awesome. Seems to be an issue with those carts. But the new flat NL replacement cart has been working fantastically.

Sorry your having issues with the usb adaptor. It has been working great for me, in fact i have 3 of them going at the same time with no problems. For what they do, at the price they are, I'm a very VERY happy customer

i can't get the update to work, and oliver's stopped replying to my emails.

i guess it's kind of hit and miss.

UPDATE
I have to say that his costumer service sometimes it's yeah so awesome: in this case he have sent me a free replacement without request from me.
I have to tell this to be honest.
Thank you Mr.Wittchow!
(But I still hate that usb-midi thing)

I have two of those fuckin' usb-midi things, and there's no way to make it work. I sent many mails to Mr.Wittchow and he answered but his solutions doesn't work and then he stop answering my mails. So to me his customer service it's not so awesome, and his usb-midi thing it's something that I hate...

he thinks that my cart's rom is corrupted or the pcb is damaged, so he sent me a usb-midi adaptor free of charge. if it doesn't work, he'll send me a new cart.

edit: in other words, his customer service is awesome.

Ok, solved.
For the people who will have the same problem, this is the solution:
press b+start+select when you see error 2, not on startup. Then visit the song editor and press select to return to the menu.
Your pattern will disappear but the card will work again.

This is your best bet, my 2.5 recently kinda did the same (wouldnt even load tho) and Oliver has just sent one out to me n i gatta return this one... hes very helpful and remotely fast

have you tried emailing oliver from nanoloop about it? i've been having some trouble with my cart, and he's been a great help.

According to the manual I tried to turn off the console and re-insert the card, but nothing...
I tried several times, pressing all the buttons like a mad and still no reaction...

Hello people, I have this cart of nl2.5 that doesn't start, when I turn on my gba sp it appear the nl logo and then, on the lower right of the screen, for a moment something like "II" and then a square. Nothing else. I try the card in another gba sp of mine but I had the same resut. Any help from the kids here?