Fire Emblem: The Sacred Stones Glitches and Secrets (GameBoy Advance)

Fire Emblem: The Sacred Stones is a Japanese tactical role-playing game for the Game Boy Advance developed by Intelligent Systems Co., Ltd. and published by Nintendo. It is the eighth game in the Fire Emblem series, the third and final game in the series to be released for the Game Boy Advance and the second game in the series to be released in North America. The game builds on the game mechanics used in the previous two GBA Fire Emblem titles Fire Emblem: Fûin no Tsurugi and Fire Emblem but is set in a different universe. Set on the continent of Magvel, the plot focuses on royal twins Princess Eirika and Prince Ephraim as they seek to discover why a longtime ally has chosen to invade their nation's borders and the sudden appearance of monsters all over Magvel.

Fire Emblem: The Sacred Stones introduces several new concepts and revives some old ones used in previous Fire Emblem games. A notable difference that separates The Sacred Stones from the previous GBA Fire Emblem titles is the use of a navigable world map, a mechanic first used in Fire Emblem Gaiden. Rather than limiting the ability to train units and buying items to story battles, the ability to traverse the world map allows players more freedom in choosing how to play the game.

Glitches

Infinite turns on Monster Maps
In any free map that has damage tiles, kill every monster or unit except for one. Then, position a few of your units alongside the damage tiles and remove their equipment, either by discarding it, or trading it to somebody else. If it works, the game's Enemy AI will move the last unit on top of the damage tile. It will then proceed to attack any units it can, until it dies from the damage received by the damage tile.

Once the creature dies, the glitch activates. Even though there's no enemies left on the map, the game doesn't recognize the last monster as "dead" and the match continues until you either Suspend and Restart, or Retreat from the fight. If this occurs during the actual story mode, as opposed to a Monster Map, the current chapter will become unbeatable, requiring you to restart the chapter.

Restore any item to new condition (including Dragonstone)
Use the Control Enemy glitch to have a monster with a flashing green "spoils" item in its inventory take the item you want restored from Supply. After making sure that your item is on the bottom of the list and is flashing green as if it were spoils, kill that monster. The monster will drop your item, however it will be totally new. This trick can also be used on gorgon eggs, but the first item on the list will disappear and you must trade with them again after they hatch to regain the item. This glitch can even restore the Dragonstone.

Secrets

Change equipped items of a character even if their turn is over.
Take any of your units up to a certain character and select the trade command. Trade your weapon of choice to the top of the character's list of weapons. That weapon will now be equipped. This can come in handy when you realize you may need a different weapon from the one you are currently equipped with.

Flyers' Triangle Attack
The Triangle Attack from Fire Emblem 7 is back, but there is a catch to using it this time around. To use it, surround the desired target on three sides with Vanessa, Tana and Syrene (whom you must safely recruit in Chapter 17), then attack the enemy. For the Triangle Attack to occur, the two supporting flyers _must_ be Falcoknights. This means that you'll have to bite the bullet and promote either Vanessa or Tana into the Falcoknight class as opposed to a Wyvern Knight.

The benefit of the Triangle Attack is that you'll get a guaranteed critical hit, and thus 3x the normal attacking damage practically whenever you want.

Infinite Support
To use this, go to the Tower of Valni and select four pairs of people you want to offer support, then start the battle, place the units that you want to support each other in adjacent spaces and end your turn. Continue ending your turns until your units can support. After you support with all your units retreat from the Tower but DO NOT SAVE. Repeat this process until you have an A-rank support with your four pairs of units.

Once you are done simply restart the mission you were on, but DO NOT SAVE. If done correctly your units should have no support records in their stats, but when you go to support conversation in extras the support records will be there. Using this glitch I completed 100% support in a matter of hours.

Member Card and Secret Shop (Ephraim Mode Ch. 14)
To get the member card from Rennac you steal it, kill him, or recruit him w/ Ephraim for 9980 gold or have L'Arachel talk to him without paying him. After getting the member card go to the left side of the stage where there is an archer holding a body ring (you have to steal the body ring). To the archers' right the secret shop will be found.

Rennac/Member Card: Chapter 14 (Eirika Mode)
When you unlock the door to the far right on Chapter 14, you will see a rogue named Rennac. He holds the member card for the secret shop. To get it, you must recruit him, kill, or steal him. If you kill him, he will drop it, but you will miss a valuable character. If you steal him, he has the opportunity to kill you, so do it at your own risk. If you recruit him with Eirika, you will have to pay 10,000g. If you recruit him with L'Arachel, he will be free, which is a big advantage. He doesn't need a lockpick to open chests and doors, and is a fairly decent fighter.

Secret Shop (Ch. 19)
On the right side of the stage (where there are 3 chests in a vertical line) there will be a reversed-upside down L. The secret shop will be on the right square.

Secret Shop (Chapter 14 Eirika Mode)
After you get the Secret Card, look near the boss. There are two upside down "L" shaped things. On the little part of the one on the left, there is a secret shop. Have someone with the member card in their inventory stop there to access the shop.

Unlimited secret books/spears
When you have cleared chapter 19, go to the Ruins. Then you enter retreat and save. Then reset the game. If you now enter the ruins, the first wight will carry a secret book. This ONLY works when you have saved while standing on the ruins on the map and reset then. If you enter the tower the same way (enter, retreat, save end re-enter) the bonewalker left of the boss will carry a spear.

NOTE: This doesn't work after you cleared chapter 20

Here's the game's ending, in case you didn't reach it yet: