You can't install a9lh on 11.4. Best you can hope for is homebrew. Even that will be tricky - I think all the free entrypoints are patched currently.
if i had the doodlebomb entrypoint(installed after 11.4 update) for the homebrew then would i be able to install a9lh?
Currently your choices are mainboard replacement or a 3DS that's on 11.3 or lower firmware.if i had the doodlebomb entrypoint(installed after 11.4 update) for the homebrew then would i be able to install a9lh?