Idk if I’d consider that a “myth busted”, as you know the common phrase in this community is “PEMN” or personal experience means nothing; you’re dealing with luck and rates. It’s entirely possible for someone to get a Roy with 5 Res at 20/20(he gets +5 Res upon promotion), and he has a growth rate of 30% in that stat.
What I’m basically saying here is, your growth increase is probably minimal at best(in FE7/FE8 the increase was +5%); you’re going to need more tests to prove this is true or not.
Also remember that you’re expecting your 10% to go off one time in 19 levels, whereas you will get +0 90% of the time.
perhaps there’s some sort of hard-coded restriction in place, where its growth boost won’t come into effect until you’re at a point in the game where you would legitimately have mercurius? i figure it’s an awfully specific thing to restrict, particularly in the nes era, but hey intsys has made hard-coded restrictions that are just as arbitrary!
19 levels with a 10% proc for 7 different stats, not 19 levels with a 10% proc for 1 stat. I got the point (PEMN) but thought you might have made an error in calculating. No procs on one stat at 10% over 19 levels isn’t out of the ordinary. But no procs on 7 stats over 19 levels? Definitely warrants further investigation.
I did some testing with the Miracle Sword. Marth would occasionally get +2 on level-ups. It looks like if Marth procs a stat, there’s a chance he will proc +2. The bonus proc seems to be a fixed chance (maybe 50%) because 100% growths does not guarantee +2 in all stats.
Edit: I set all of Marth’s growths to 10% and he still gets +2 procs sometimes.
Unlike the GBA FE’s there’s no separate byte to keep track of the duration of the Barrier staff. Resistance decreases by 1 every turn unless the resistance stat is “negative” (has the 0x80 bit set). The 0x80 bit is switched on when the Talisman item is used and will stop resistance from decreasing. So, if you wanted a character to start with 20 resistance (that doesn’t decrease) you would use 0x94 (0x80 + 0x14) for the base stat. Also, the Barrier staff and Talisman set resistance to 7 rather than add 7 resistance, so you can’t stack multiple Talisman or use Barrier + Talisman to have 14 resistance. This also means resistance will be lowered to 7 if those items are used on a character with greater than 7 resistance (actually, the Talisman doesn’t work correctly if (resistance AND 0x7F) > 120 but that doesn’t really matter)
Edit: Forgot about Pure Water.
If the character doesn’t have the Talisman flag, then it sets resistance to 7 (just like Barrier)
If the character does have the Talisman flag, it has no effect and no uses are consumed (unlike Barrier which will still set resistance to 7)