Hi. I once upon a time (around April of 2020) did actually create such a cheat code. It isn't working perfectly and often softlocks the game in cutscenes, but it works for all intends and purposes. It uses a glitch that is used in speedruns, "Walk through Air" as we call it, or walking in the air. What the cheat code does is whenever the A button is NOT pressed, it activates the glitch + "ground state", but when we press the A button it temporarily deactivates the glitch and goes into a "jump state". Once we release the A button, the "ground state" is activated again along with the glitch, allowing us to stand in mid-air and then jump again in mid-air. It is, however, very broken and not ideal. It seems to work better on some versions than others; it seems to work better on EUR 1.0 than 1.1, same for US 1.0 being better than 1.1 (even though for the latter case, it's the exact same cheat code).
The .txt file in the attachment of the post has the "Infinite Jumping" cheat code for all versions of the game (the only version that hasn't been tested is 1.1 JP due to not being able to update it). You will need to rename the text file to the titleid of whatever version you have, though, but it does work.
I have been intending to create a lot of cheat codes that I would then later put in FlagBrew's Sharkive cheat database on GitHub (which is connected to the Checkpoint Homebrew app, which allows people to use the cheat codes I put there), though I am quite not yet finished with all of it, but it is coming! Sooner or later... I have a lot of projects with this game both cheat and speedrun related lol.
For the EUR v1.0 version to explain what is happening in each line (it's the same across the three cheats in the .txt file in the same order, but with different addresses:
Code:
[EUR v1.0 Inf Jumping]
D3000000 17000000 --- Offset = 0x17000000
203E2DE0 00000000 --- Mario's Dream World Jumping state, 0x00 = "stand in mid-air" glitch always activated
20436958 000000A0 --- Mario's Real World Jumping state, 0xA0 = "stand in mid-air" glitch always activated
DD000000 00000001 --- If the A button is pressed, then:
203E2DE0 00000003 --- Mario's Dream World Jumping state, 0x03 = "is jumping" effect (glitch still activated)
20436958 000000A3 --- Mario's Real World Jumping state, 0xA3 = "is jumping" effect (glitch still activated)
D2000000 00000000 --- END MARIO's CHEAT
D3000000 17000000 --- Offset = 0x17000000
203DE5D8 00000000 --- Luigi's Dream World Jumping state (same values as Mario's for everything)
20432138 000000A0 --- Luigi's Real World Jumping state
DD000000 00000002 --- If the B button is pressed, then:
203DE5D8 00000003 --- Luigi's Dream World Jumping state
20432138 000000A3 --- Luigi's Real World Jumping State
D2000000 00000000 --- END LUIGI'S CHEAT