Item description:

In the original SNES FFII (and SFC FFIV) the Immune Byte was bugged in that the character who had an item with the Immune Bit equipped, was given 99% Evasion and if it was removed they had a lingering x4 Weakness to Fire and Ice. This patch fixes both behaviors, for the Immune byte-99% Evasion fix the storing of the Immune Byte “temporarily” is no longer put in the same place as Evasion and is instead moved to a free section of RAM where it does not interfere with later Evasion calculations. On that same note the game never properly decrements the bits that contain x4 Weaknesses by a bizarre choice of design and oversight, it only took two NOPs (which doesn’t effect anything else at all) to fix that behavior.