Bug Details

System(s)	Playstation, PSP, PSN (POPS)
Bug Type	Gameplay
Region Introduced
Patch Version	2.01.065b

Regions Affected

This is a rare type of bug in that it originated in the Japanese version, and was fixed before the European release. Most bugs that affect the Japanese version were never fixed by Konami.

This is the most commonly used method for exploiting the bug.

1. Remove the armor from, or strip a minimum of two characters who can wear the same armor as the Hero.
2. Equip the Hero with the armor you intend to buy. Typically, Dragon Armor is used.
3. Make sure the party's potch supply is just slightly more than enough to buy one of the item above. Dragon Armor costs 23,000 potch, so a range of 23,000 to 30,000 is advised.
4. Go into the Armory and choose to buy Dragon Armor.
5. When asked what to do with it, choose "Equip".
6. Select the Hero as the character to equip the armor.
7. The game will ask what to do with the armor the Hero is already wearing. You will have the option of putting it in the bag, or selling it. Instead, press the cancel button, and back up one menu.
8. The game will again ask who to equip the purchase to. Choose one of the characters you stripped (the armor slot must be empty).
9. After equipping, the game will not back out to the purchase menu, and instead allows you to continue selecting people to equip the purchase to. The potch display will not have updated after your last purchase.
Choose the other character you stripped. The armor will be purchased and equipped. (You can optionally continue equipping the same armor to more characters, if you wish. Note that if you select one who has armor, you will have to choose what to do with it, and selecting either option on that screen will end the exploit.)
10. Cancel out of the Equip menu (or buy another set and put it on someone who has armor). When the game drops you back to the purchase menu, you will have far more potch than you started with. If you do not equip more than the two characters you stripped for the purpose, you should have 999,999 potch.

The following method uses two characters instead of three, and has fewer steps, depending on how you count. However, it does require a little more thought to use. It also exploits the bug in a slightly different manner.

1. Have just slightly more than the purchase price for a piece of armor. This way is a bit more fiddly, since you may be getting potch back at one point, so aim for around 25,000, if you are using Dragon Armor.
2. Remove the Armor (shield, whatever) from one character.
3. Have another character that can wear the same type of armor you plan to use for the exploit. Their equipment does not matter.
4. Choose to buy the equipment, and choose to equip it to the second character (the one who is still wearing his gear). Go through the menu to the point of choosing to exchange or bag the existing equipment, just like in the well-known version.
5. Press the cancel button once.
6. Choose the character whose equipment you removed to receive the purchased item now. The sale will go through, that character will be equipped, and you will be left on the "Equip Who?" screen. After this, you should only have a few potch to a few thousand potch left, depending on what item you are exploiting.
7. Choose the same character again. You can exchange, or bag the item, and the purchase will still proceed. If you exchange, the purchase price must be more than your current potch plus the money you get for selling back the armor. In other words, your current potch has to be less than half the price of the armor you are exploiting, after you have bought the first item.

Firstly, the game uses a single, multipurpose routine for managing the party's potch. Depending upon the first argument supplied to it, the routine will retrieve the current potch amount, add (or subtract) potch, or set the potch variable to a particular value. This routine does not take into account the possibility that subtraction may result in the potch variable having a value less than zero. Behavior of this sort is reasonably safe, but it assumes that calling routines will not try to subtract 23,000 when the party only has 7,000 potch. When the potch variable underflows, it appears to be an extremely large positive value, and the management routine sets it to 999,999.

Secondly, while you are in the Equip menu, the shop's programming believes that the price has already been checked against your potch reserves. Normal behavior in this menu would be to back up to the Purchase menu after equipping once, but when the player backs out of the Bag/Sell selection in step 7 (Method 1), the menu mangles its own state. As long as the armor is then equipped to characters who are not wearing something else, the game will allow the purchase and will stay on the Equip screen. Since the price is not compared to the potch the party has, additional purchases can be made. Each additional purchase will subtract more potch.

1. At the beginning of the exploit, the party has 25,000 potch on hand.
2. In the purchase menu, 25,000 is compared to the 23,000 cost of Dragon Armor. The purchase can proceed.
3. After backing out of the Bag/Sell option, the armor is equipped to someone naked. Potch is now 2,000.
4. The game does not check potch, and allows an additional purchase to be made. Potch is now -23,000 (0xFFFFA628). The game handles potch as a unsigned value, so this appears to it to be over 4 billion potch. It sets it back to the maximum allowed, 999,999.

The code responsible for this is in /CDROM/140_HONP/HDOUGUYA.BIN. The amount of code involved is extensive, and will not be covered here. The Potch Management routine is in the main executable (name varies by region).

; Suikoden II Castle Armory Fix 
; Written by Pyriel
;
; This is an attempt to correct the issue with the castle armory
; allowing you to buy items you can't afford at one point in its
; menus, which results in your potch falling below zero and being
; reset to an enormous value.
 
.psx
.align 4
 
.openfile HDOUGUYA.BIN, 0x8010DC50
.org 0x80113CD0
	addiu $v0, $v0, 0x0E48
.close