I hacked my 3DS on the "second wave". Didnt even know about the "first wave". How was it? Why is it separated? Was there any problem with the first wave going to the second?
4.5 with spider/MSET. 9.0/2 was blown open, as with 11.
I believe there was the addition of Miiverse and a few other notable changes that prompted others to want the update.
Plus, the money. Initially 3DS was wayyyyyy overpriced, so not too many folks had one; by the time 9.0/2 rolled around, there were more owners of a 3DS, so millions of people missed out on 4.5. Hell, I jumped on the 3DS bandwagon around 7.whatever after giving up on 4.5.
TL;DR, reasons.
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As for when I'll hack Switch, Soon™ (ya tu sabe.) A.K.A., you already know.
I actually plan to buy two or three more Switch units (one for my ladyfriend, one for official online, and one for MarcusD, if he should agree to give back to the community), so I'll deal with it as it rolls out, but I'm definitely getting a TX jig for "girlfriend-mode".