Firmware 3.15

I installed the 3.75 this morning on my TV, but I still can't get it to read the USB keys.

In the manual, it states that my model, the 32HL3000, is not compatible with the USB function, but with the information I have received, it is indeed possible to read USB files in jpg, avi., mp3, mp4 formats when installing version 3.15. The files on my USB stick are in the recommended formats.
Already having version 3.75 and since my files are in the recommended formats, I don't know where the issue lies?

Hi,
I finally managed to download the famous firmware 3.15 and will proceed with the operation
I will keep you updated on what happens next and thank you in advance for your help.

Activation successfully completed,
I am so happy and I probably would never have been able to do it without your help, thank you so much.
I am overflowing with joy right now, thank you very much.
After the firmware downgrade, the new menu appeared with the USB function active, I believe I managed to contain my joy. After the activation, I did another update to 3.75, the sound and image are correct.
Thank you so much.