I actually got something different after some retries.
After some percussive maintenance, I was able to get it to actually successfully load the save and get past the "Data could not be read error" and get to at least "this save file is corrupted" again.
So I noticed that Checkpoint would take different times when trying to load a save. Frustratingly, Checkpoint doesn't really seem to show any errors regardless of if it successfully dumped the save or not.
From the best of my ability
20s: Timeout, could not load the save but there was nothing that stopped it
1s: Immediate error. Maybe cannot reach the cart
4s: from the one time that it successfully loaded the save
I seem to recall seeing somewhere that these cards have a separate memory chip in them. Is it possible that the internal contacts are going bad and losing connectivity from the main board to the chip? I've cleaned the external contacts multiple times already.
After some percussive maintenance, I was able to get it to actually successfully load the save and get past the "Data could not be read error" and get to at least "this save file is corrupted" again.
So I noticed that Checkpoint would take different times when trying to load a save. Frustratingly, Checkpoint doesn't really seem to show any errors regardless of if it successfully dumped the save or not.
From the best of my ability
20s: Timeout, could not load the save but there was nothing that stopped it
1s: Immediate error. Maybe cannot reach the cart
4s: from the one time that it successfully loaded the save
I seem to recall seeing somewhere that these cards have a separate memory chip in them. Is it possible that the internal contacts are going bad and losing connectivity from the main board to the chip? I've cleaned the external contacts multiple times already.