With the latest firmware 1.02, I noticed some stability problem I didn't get with the previous version.
For now, Bleach DS and Castlevania Dawn of Sorrow, freezed regurlay during playing. I'm quite sure I had the same problem for other games such as Dr Kawashima and Mario vs DK2, march of the minis.
Did you get the same with this firmware? Did you get it also for the previous version? If not, I think the best is to go back to the 1.01.