Difference between GEN-B and GEN-D2?

Hi! I have 4 questions: 1- What's the difference between GEN-B and GEN-D2? Which one is newer?
2- Have you ever had a homebrew which worked under m33 but didn't work under GEN? (Because everyone says it has no problems)
3- I have a m33-3 3.90. You think I should upgrade to GEN? (Considering that I care more about homebrews and emulators than actual PSP games)
4-Thank You!

GEN-D2 is the latest

but more "recent" is GEN-B for HEN (homebrew enabler)

you dont need to worry about that though


if you dont care about playing new games on your PSP, then stay on 3.90M33-3
but if you want to play anything that came out in the last month or so, go to D2

Thanks a lot!