elfpack needs to be patched in FW. It is the most world-opening patch for your phone, as it offers to load compiled .c code during runtime as elf files. Elf runs 'bare-metal' on OS, if it crashes, your phone mostly does too. Elfpack consists of elf-loader and elf-library. Get elfpack builds here.
Elfs usually come with or create a .bcfg file for app configuration. Often they come with other files like images, text or binary files. Install correctly, follow the guides.
You can run elfs as daemon too (=autostart on unlock after boot).
See the sticky threads here for tutorials: https://www.topsony.com/forum/forumdisplay.php/65-Elfs-Pack
Also learn about fundamental elfs: https://www.topsony.com/forum/showthread.php/24362-IMPORTANT-Elves-pack-to-run-elf-to-ur-Sony-Erisson-Phones
Definitely get Bookmanager elf <insert here> - it is the “task manager”. Books are the open pages in OS. Bookmanager has elf management.
Dyn stuff is the library part for elf loader. You can port DYN too and compile e.g. with IAR embedded
#TODO

directory structure:
/usb/other/ini <-(*.ini) files
/usb/other/ZBin <-(*.elf) files
/usb/other/ZBin/Config <-dyn_const.bin + other (.bcfg) config files
/usb/other/ZBin/Deamons <-"autostart" {(*.elf) start on phone startup}

https://archive.perk11.info/elfse/

Compile yourself, also see Elf source codes.