Talk:List of shops in Mario & Luigi: Partners in Time

Actual internal shop upgrade requirements

To update this article to, uh, actually list the shop inventories after not having them for 15 years, I needed to figure out when the shop upgrades/unlocks happen. I replayed through the entire game and made save file backups as I progressed. I noted when shop upgrades happened but I still did not have a full understanding of it. That is because the game has a set of flags somewhere in memory that get set, and having these flags set is what causes the shops to have more items. This is how Superstar Saga and Bowser's Inside Story work, so Partners in Time likely worked the same way. So to really know the unlock requirements, I did some searching through my save files and RAM searching with the game running in Bizhawk and eventually found the shop flags. But something weird is going on with how PIT sets the flags: these shop flags only get set if a shop room is entered with the correct story progress. The other games will set them during things like cutscenes where bosses get defeated in the field (so if you find the value, you can see it update in real time to know the exact event), but PIT does not do that. This means that I needed to do a bit more digging to figure out better ideas of when the flags get set. This involved doing things, going back to a shop, then seeing if the shop flags update. This is the actual internal requirements (assuming you did the action and then entered a shop room):

• Flag 1: gets set after automatically time-warping back from clearing Vim Factory. This is easily observable in normal play.
• Flag 2: gets set after automatically time-warping back from clearing the Yoshi's Island region. This is interesting because of the how the Yoob's Belly segment cannot be left early and how there is a brief moment of gameplay before getting back the 2 Cobalt Star shards from Baby Bowser. I was able to confirm that this is the actual unlock requirement by using cheats to leave without activating the related cutscenes. This is NOT easily observable in normal play.
  • This availability requirement is listed on the main article as "Available after clearing Yoob's Belly at Yoshi's Island." because that is when the player can normally see this upgrade (and is a more understandable explanation).
• Flag 3: gets set after automatically time-warping back from clearing Gritzy Caves. If you defeat Petey Piranha and go to a shop before finding the fake Peach, then the shop does not update. This is easily observable in normal play.
• Flag 4: gets set after clearing Thwomp Caverns. This is the really interesting one because after the caverns, you get forced into the Shroob Mother Ship segment and cannot enter a shop during this. I was able to confirm that this is the actual requirement by using cheats to leave the Shroob Mother Ship without doing anything there. This is NOT easily observable in normal play.
  • This availability requirement is listed on the main article as "Available after being dropped into Toad Town by clearing the Shroob Mother Ship." because that is when the player can normally see this upgrade.
• Flag 5: gets set after clearing Toad Town. "Clearing Toad Town" is defined as hitting the second set of Simultaneous Blocks to open the gates to the room with the pipe to Star Hill. This pipe room also has the ! Block to open the path to a time hole. This is NOT easily observable in normal play, because it is unclear if this unlock is actually part of the Thwomp Caverns unlock.
  • This availability requirement is listed on the main article as "Available once access to Peach's Castle is regained by clearing Toad Town after the Shroob Mother Ship." because that is when the player can normally see this upgrade. I'm deciding to keep it listed as "availability group 5" for consistency with the rest of the article (so that there are not two completely different availability requirements claiming to be group 4).

If you have the North American (USA) version of the game and are willing to mess with this in Bizhawk, 33C065 is the address in RAM for the shop flags, and 207868 is the 2-byte address in RAM for the current room. For the shop flag address, the upper 5 bits are the shop flags, so setting the shop flag value (in binary) to 00001000 will give the first upgrade, 00011000 gives the second, and so on. Also, the second lowest bit in that value controls if you have the Baby Cakes move, because the byte before this one has flags controlling what moves you have. I was able to check all shop inventories in all possible upgrade states by editing this byte. For the room number address, touch a loading zone to cause the game to fade to black, pause the emulation, set and freeze the room number address to 0099 (this is in hex), then unpausing will cause room 0099 to load instead, which is the Shroom Shop room in Peach's Castle. This was how I left places like Yoob's Belly and the Shroob Mother Ship early to confirm those unlock requirements.

I am dumping this info on the talk page so that the true technical info is written down somewhere, instead of being on the main article with the information looking dubious. This is info that best has a citation to go with it, and leaving it as [citation needed] does not sit right with me. I could make a video (essay?) showing this information to use as a source, but I have no experience with video editing and how to present this type of information in an obvious way that is nice. Dumping this info here also has big "source: trust me" energy, but it is better to dump it into the talk page for additional commentary instead of making a bold claim in the mainspace. --Spencer PK (talk) 00:35, August 4, 2025 (EDT)