Sony has just made available to download the new official firmware 6:37 for the PSP. According to the description given by the same company, this update will improve system stability when using certain functions. In reality it is much more likely that this is due to the need to update by Sony to plug the security hole used by the kernel and perhaps the HEN exploit demo of Everybody's Sukkiri.
Update: Patches all Known Exploits. Do not Upgrade your PSP to 6.37