In some throughput intensive applications, using LE Data Length Extension feature introduced in Bluetooth 4.2 can be helpful on the application performance assume all devices support Bluetooth 4.2 in this scenario.
AmbiqSuite SDK come with default LE Data Length setting which is 27 bytes. To use LE Data Length Extension, below changes need to be adapted.
1. Get EM9304 Configuration Editor from below link
2. Generate a configuration patch that increase "Max Packet Payload" to 251 in "Platform" tab
3. Upload the configuration into IRAM and give it a unique "User Build" number and "Patch ID". "User Build" number 0 is reserved for official EM patch. This procedure requires a Apollo2Blue EVB connected with your laptop and runs with em9304_test_bridge firmware.
4. Read the patches from IRAM and locate the patch we just applied and save it into a emp file.
5. Put the emp file into folder “AmbiqSuite\tools\emp2include”
6. Run “emp2include.py -o OTP” in command line
7. Follow below Knowledge Base article to change ATT MTU size to 251 bytes
8. Rebuild your project and it's good to go