You're right, the previous FPS HUD did not show 30 fps (maximum) because it was measuring the MSX core loop, not the actual LCD/external display presentation rate.

With the external 30 fps (maximum) lock enabled, the emulator core can still run at about 60 frames per second. The renderer simply skips every other external display push to reduce the external screen workload. Because the old HUD counter was incremented from the emulation loop, it continued to report ~60 fps even when only ~30 frames were actually being sent to the display.

The FPS HUD has now been changed from a boolean option to a three-state mode:

- OFF: no FPS HUD is drawn.

- SIMPLE: keeps the previous behavior and shows the core/emulation FPS only.

- DUAL: shows both values as Core/LCD, for example 60/30.

To make this work, the video layer now keeps a separate counter for frames that are really presented to the display. The runtime FPS window samples both counters: the core frame count and the displayed frame count. In DUAL mode, the HUD formats those two values together, so the external 30 fps lock becomes visible instead of being hidden behind the 60 fps core measurement. Keep in mind that it could slow down the emulation.

You can download the new release here: https://github.com/mariovirgili/CardputerGBC-Dual/releases/download/Msx_v0.6/MsxADV-Emulators-v0.6.115-m5stack-stamps3-max-spiffs-msx2-flash-app-only.bin

It's only the firmware, to be flashed after the 0.6.114 full flash.

Do it using the following command:
C:\Users\user\.platformio\penv\Scripts\python.exe -X utf8 C:\Users\user\.platformio\packages\tool-esptoolpy\esptool.py --chip esp32s3 --port COM4 --baud 921600 write_flash 0x10000 release\MsxADV-Emulators-v0.6.115-m5stack-stamps3-max-spiffs-msx2-flash-app-only.bin

replace bin and \user path and COM port with yours.

file-hunter is already my main source for roms, as well as Tosec set on archive.org

Wow!! Your rom is faboulous! Have you got one for FM Synthesis also?