I found this over at another forum. I tested with PiMP Streamer and WiFi Sniffer, both didn't work before the update (without doing the switch trick) and now both work 100%!!! Here are the details:
This update fixes a secondary effect that 3.51 wlan.prx caused in 1.50 wlan.prx,
which made wlan homebrew not to work.
Ths issue was caused by sony code of 3.51 wlan.prx, and not by M33 code.
It doesn't happen replacing 3.51 wlan.prx with 3.40 one.
- M33 Team