OSMC and Adafruit 5" 800x480 TFT

Hi,

I would like OSMC to work with my Adafruit 5" 800x480 TFT touch display Overview | Adafruit 5" and 7" 800x480 TFT HDMI Backpack | Adafruit Learning System

Unfortunately every time something on the screen is “refreshed” it shows what you can see in the picture here for 5-6 seconds before showing the normal thing again. Do you have any idea?

I have set the following options in config.txt

hdmi_edid_file=1
hdmi_group=2
hdmi_mode=1
hdmi_mode=87
max_usb_current=1
hdmi_cvt 800 480 60 6 0 0 0
disable_overscan=1
over_voltage=0
sdtv_mode=2
force_turbo=0
disable_splash=1
core_freq=450
initial_turbo=0
start_x=1
sdtv_aspect=1
gpu_mem_1024=256
hdmi_force_hotplug=1
arm_freq=900
hdmi_safe=0
over_voltage_sdram=0
sdram_freq=450
dtoverlay=hifiberry-dac-overlay
hdmi_ignore_cec_init=1