Unfortunately we cannot install Custom Firmware on your PS3.

But you can install PS3 Homebrew Enabler (PS3 HEN)

What is the difference between Custom Firmware (CFW) and Homebrew Enabler (HEN)?

-CFW is compatible with all current homebrew and works automatically when you turn on your PS3

-HEN is currently not compatible with all homebrew and requires you to reactivate every time you turn the PS3 on.

To reactive HEN you just need to click on one icon on your Game column. Some examples of currently not supported Homebrew is CCAPI

See here for more information about compatible Homebrew https://www.psx-place.com/threads/ps3hen-homebrew-compatibility-chart.24016/