Do we have any more context as to the problem? If it needs an item then that can possibly sorted more easily than some other things, also if there is an item that can teleport you to places then that is also not a bad plan to have some cheats
If you are on a flash cart do bear in mind you can transfer to an emulator for fiddling purposes, and if you have a real cart you can possibly do something but depending upon what you have then EEPROM can be fiddly.
Various choices here.
1) Kill your characters -- the same health cheats
that put you are 9999 health always can be twisted to be 0 health. Activate those and if death spawns you back you have your solution. If death will not work (say restores you right back there or has too many negative consequences you can't easily undo -- experience and money can be restored with cheats
(short version is unencrypted cheats, which should be many you find, are a cheat type, cheat location and maybe cheat payload/what you write to that location, change the max value to 0 instead and you have the kill player cheat). https://web.archive.org/web/20080309104350/http://etk.scener.org/?op=tutorial
if you are unfamiliar with cheats and no existing cheats are available for what you want.
2) Location cheat. For the GBA on non single screen games there is probably a virtual location. Figure this out (can probably do it with conventional cheat search, be it on a new game or on that screen if you can move, as moving location will change something in memory) and do a write to relevant locations to put you the other side of the room or wherever you need to be.
2a) would be walk through walls if that is a thing that is needed. Same thing for virtual location, but when you bump into the limit for it you find the code handling it (or maybe some kind of virtual map in memory of valid locations). This will probably involve fiddling with some assembly unless there is an equip or mode within the game (some cutscenes can be this) that can achieve a similar effect.
3) If you have to replay the game it might be possible to transplant any stats, money and inventory from that to your new save. Find where your stats are and either combine savestates (all the inventory parts from your broken save with the new save/existing save and hope there are no checksums to trip you up), or make enough cheats to approximate it/replicate it (if there existing cheats for all items, max experience... then tweak those)..
4) You figure out what is wrong and activate the things necessary for it -- if the game sees an item in your inventory, sets a flag and removes the item but you say spawned back with no item and no flag to drop the bridge or whatever then you find the flag, or maybe the item if that is easier). Ignoring the item thing if you have a save just before then I presume you would have done that, and if replaying the game was easy I imagine you would have done that too. However if we were being proper hackers this would probably be what you want to figure out and share with others. You could still figure out the flag if you can maybe leave and enter the room as it might well check something upon entry/stepping on the first tile, however we are back to playing with assembly rather than simple cheats.
3) and 4) you would probably do with conventional save editing rather than RAM and whatever else approaches if you really wanted to. Might be harder as you also have all the fun of save editing on top of that but some do like to make them to help others fix their issues.