I tried all of the save types, and still could not get Puyo Puyo Sun 64 (J) to boot up.
I was doing it this way:
1. Highlight game and choose Select Only.
2. Using the Z button, change the save type to whatever.
3. Start the game using the usual option Select and Start.
The problem was using Select and Start to boot the game.
Use the Start button on the controller instead, to properly boot it.
Use EEP4K to boot Puyo Puyo Sun 64 (J).
Use SRAM or SRAM128 to boot Jinsei Game 64 (J).
Even after trying this method, there is one single game I'm not able to boot.
Could someone else confirm this?
BattleTanx (U) [Expansion Pak incompatibility?]
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Edit:
Here's some ROM names to play these European releases on a NTSC console.
Airboarder 64 (E) [f1] (NTSC)
Centre Court Tennis (E) [f1] (NTSC) [aka Let's Smash (J)]
F-1 World Grand Prix II (E) (M4) [f1] (NTSC) [Change Game Mode setting from Default to NTSC.]
Premier Manager 64 (E) [f2] (NTSC100%) [Full color, but not properly aligned on my TV.]
Rakuga Kids (E) [f1] (NTSC)
Taz Express (E) (M6) [f2] (NTSC) [Full color, but not properly aligned on my TV.]