Yes, you can, using a tool called . However, you should be aware that the original Modoru tool was patched by firmware 3.73, so you will need to use an updated fork or version that is confirmed to be compatible with 3.73. A downgrade is often performed to achieve a permanent hack like Enso or to improve compatibility with older homebrew. After downgrading, all data on the console is typically preserved, but it's always wise to back up your important save data.
Go to Settings > System Update > Update using Wi-Fi . ps vita firmware 373 download better work