Golden Sun: The Lost Age featured an unlockable Hard Mode that boosted enemy stats, which wasn't present in the first game - until now.
This is a simple patch that applies TLA's Hard Mode stat boosts to GS1 - specifically, enemy HP is increased by 50%, and enemy Attack and Defense are each increased by 25%. That's it - no other difficulty or balance changes are applied. To be clear, this patch simply directly applies the enemy stat changes to the game - it doesn't add in a selectable "Hard Mode" option into the game like how TLA Hard Mode is accessed.
Apply to a clean ROM for best results - however, since this patch only changes enemy data, I think you'd be fine to apply it to a modified ROM as long as the enemy data was untouched. But as always, be sure to keep backups and whatnot.
You can grab the patch here: GS1 Hard Mode.ips
This is a simple patch that applies TLA's Hard Mode stat boosts to GS1 - specifically, enemy HP is increased by 50%, and enemy Attack and Defense are each increased by 25%. That's it - no other difficulty or balance changes are applied. To be clear, this patch simply directly applies the enemy stat changes to the game - it doesn't add in a selectable "Hard Mode" option into the game like how TLA Hard Mode is accessed.
Apply to a clean ROM for best results - however, since this patch only changes enemy data, I think you'd be fine to apply it to a modified ROM as long as the enemy data was untouched. But as always, be sure to keep backups and whatnot.
You can grab the patch here: GS1 Hard Mode.ips


Downloads: Version 1.5 is the newest version of the hack, and the first version of the hack available for the first game. 1.5f is a fixed version of the TLA patch only, which was accidentally released as an older version with several errors. Since downloads are not currently functional on the site, for the time being these hacks will be hosted off-site here:
Changes from Previous Versions: In case you want to know what's changed with each update, here are in-depth changelogs for each version.
Screenshots:


About the Hack:
General Class standardization:
Venus
Mars
Jupiter
Mercury