Emulator saves might not have the save layout as the saves found on real cartridges and some conversion needs to be applies before they can be transferred from on to another.
There are several conversion utilities available:
Cart Reader V5
Overview
Supported Systems
List of user-created Adapters
Community Discord Server
Build Guide
Recommended Tools
What to order
How to build
More Information
How to order a PCB
How to flash the Arduino
Flashing the snesCIC
Preparing the SD Card
Automatic Voltage Selection
Real‐Time Clock
Advanced
Troubleshooting
Calibrating the ClockGen
Designing your own Adapters
Serial Monitor
Savegame Conversion
Older Revisions
About
Cart Reader V4
Cart Reader V3
Cart Reader V2
Cart Reader V1
Firmware Archive
Nintendo 64
Read N64 cartridge
Reading a Controller Pak
Reflashing N64 Repros
Reflashing a Gameshark
Super Nintendo
Reading SNES/SFC carts
Reflashing NP carts
Reflashing SNES/SFC Repros
Reflashing BSX 8M carts
NES and Famicom
Dumping NES Games
Adding auto mapper to a game
Game Boy
Reading a Game Boy rom
Reflashing NP GB Memory carts
Writing custom flashcarts
Game Boy Advance
Reading a GBA save game
Reflashing GBA repros
SEGA
Reading Mega Drive Genesis games
Reading Master System games
Other
Flashrom Programmer
Flash-Adapter
AM29F016-AM29F032
MX29F1610
MX29L3211
MX29LV160
MX29LV320
S29GL032
39F040 PLCC32