Thanks to Devhook, I still run only the 1.5 firmware for my PSP. Yesterday, since my wife was using my laptop, I had no other option but to browse the net on the PSP. I was surprised that I could not connect to my APN using my emulated 2.71 firmware. It is quite sometime since I used the Wi-Fi on my PSP but I could not recollect an instance where it failed to connect to my home network. I use WPA AES encryption and was repeatedly getting a stupid 80410D05 error message. If I change the encryption, I got a nice 80410D06 message! What an improvement!
The fix (after some extensive Googling) is simple. This seems to happen to folks using the linksys router. Login as administrator in your router, go to Wireless-> Advanced Wireless Settings. You’ll see a combo box for Basic Rate among others. Change the value from default to 1-2 MBps and save your settings. Now try reconnecting your PSP. It should work.