I know it's been a lot of time since that post, but I remembered it and decided to come and ask for help.
I don't quite understand what exactly is failing.
What I'm trying to do is to attach jiangzhengwenjz's EV/IV Screen for Emerald onto my Theta Emerald EX ROM for personal use.
I inserted the routine from the main post at E1ABB0
Changed "XX XX XX" to "EF 04 80" since 8004EF is where I've inserted the script that would allow me to activate the EV/IV Screen.
I already configured the Item that I want to use for this accordingly too (Index 34 because it comes after the Green Shard, Use-of-SELECT and the field usage on Item Manager is "8E1ABB1").
I left all the files from jiang's code by default, so the callasm 0x8F90001 should work perfectly on my ROM. This is the script I've attached to the item
And finally, this is the result: