Your PSP runs a certain software called firmware. If for streamyx combo Tmcommy a PSP that runs official firmware then you might want to consider downgrading. People who have downgraded their PSP to firmware 1.5 have upgraded their PSP again with custom firmware which allows you to run home brew on broadband installation PSP and run games from your memory stick.
If you have already downgraded your PSP then you are aware of the fact that custom firmware gets updates frequently. The latest patch is 5.00 M33-6. You can install 5.00 M33-6 very easily, whether you already have 5.00 custom firmware or if you're upgrading from a M33 custom firmware below 5.00 M33.
What you will need is the update file for 5.00 M33-6. Then you need to unzip the file and put the UPDATE folder into your GAME folder of your PSP. If it asks if you want to overwrite then select "yes". If you have a PSP with M33 custom firmware below 5.00 then you need to find the official 5.00 firmware and rename the EBOOT file to 500.PBP and put it in the update folder.
Go to "Game" -> "Memory Stick" and select the M33 installer. Press X and you will have installed 5.00 M33-6 custom firmware. if you're also installing from a firmware version below 5.00 M33 you will now after pressing X have to select your timezone and similar options. In the end you need to press X to finish the installation. Now you will get a blue screen and you need to press O, do this or your PSP gets bricked. Now your PSP will reboot and your PSP will be running 5.00 m33-6!
The bug fixed in 500 M33-6 allows booting your PSP without memory card. PSP games are loaded quicker from the memory stick as well, but that was already implemented in the very recent 500 M33-5.
For the best, easiest and safest guides on hacking your PSP go to Custom Firmware.com
For more details on how to upgrade your PSP to the latest custom firmware, check out the 5.00-m33-6 guide.