Status screen overload via HP (FR/LG)
Posted by: VaeporSage
Date: 2013-04-21 08:22:00
Status screen errors
If a Pokémon with "negative HP" is traded to Pokémon FireRed and LeafGreen from another version, the status screen becomes unstable when the information regarding that Pokémon is stored into the game RAM. If the status of the relevant Pokémon is viewed and the player switches to another Pokémon, the game will often freeze, this might suggest that in FireRed and LeafGreen, the pointers used in the status screen for an amount of HP too large will not hold the amount of HP on the status screen for a previous Pokémon but rather change the value of another unrelated byte, causing instability.
~~~
Two years ago, I investigated this effect with varying quantities of health and observing the threshold of glitch effects within the range of HP possible. (i.e. [Max HP] to 65,535.)
Here are some of the possible effects on the game.
http://www.youtube.com/watch?v=e6UYaH-FDCI
http://www.youtube.com/watch?v=zrBND5m-9dQ
Using a Chansey (through use of Softboiled to consistently decrease its health), I found that when its HP dropped to (I can't remember exactly, but it's irrelevant anyway) around 48,000, the glitch effects on the status screen would stabilise and the game would no longer freeze.
However, on testing again this morning, I realised that I had made an error, and that the precise value of health involved is not actually a factor in creating the glitchy effects.
My Chansey, with 64,500/503 HP, has a perfectly stable status screen that does not cause freezes, sprite disappearance or glitchy graphics.
However, my Arcanine with 9764/166 HP, causes all of the above effects on viewing its status screen.
~~~
So this is where I need help: in causing the information overload, what factors precisely are causing the game to crash?
Previously, I had believed that a spectrum of effects from 167/166 (not very glitchy) to 65,535/166 (very glitchy) would be the case, but seeing as health is not the root cause of the variation in glitch effects, this glitch is impossible for me to exploit.