I turned from Raspbian to Ubuntu 19 32bit on my RPI4 because I need this distribution. I downloaded it using the RPI Imager. I had a working pinout on Raspbian, mapped on config.txt for the I2C and SPI display. Where is this config.txt file and how to map the GPIO in Ubuntu? I have read some posts about the installation but this point is not so clear for me. Raspi-config is only supported in Ubuntu Mate. There is one config.txt file on /firmware/ path. Should I modify this file? What are the proper steps to configure the GPIO?
I tried to modify firmware/config.txt, usrconfig.txt and also the config.txt at same location when havins raspi-config installed in Ubuntu Mate. Always the same result... After modifiying the desired configuration and reboot, the RPI4 enter into a loop trying to boot: the color image blinks, and immediately turns off. Then boot again, a blink of the colored image, turn off... and so on.
The configuration looks like:
#i2c, i2s, spi... are deactivated dtoverlay=i2c-gpio,bus=3,i2c_gpio_sda=23,i2c_gpio_scl=24,i2c_gpio_delay_us=2 # DPI Video Setup dtoverlay=dpi18 overscan_left=0 overscan_right=0 overscan_top=0 overscan_bottom=0 framebuffer_width=854 framebuffer_height=480 enable_dpi_lcd=1 display_default_lcd=1 dpi_group=2 dpi_mode=87 dpi_output_format=458773 hdmi_timings=854 0 14 4 12 480 0 2 3 9 0 0 0 60 0 32000000 3
I am stacked here, so this works perfectly in Raspbian. What is different and needs to be done in ubuntu to get the i2c and DPI running?