please use below image ,it just support boot from SD card and eMMC flash
2021-01-29-ubuntu-mate-20.04.1-desktop-armhf-ext4-v5.4.35-bpi-f2p.img.zip: Ubuntu Desktop system, Support HDMI interface to display Desktop.
2021-01-29-ubuntu-server-20.04.1-armhf-ext4-v5.4.35-bpi-f2p.img.zip: Ubuntu Server System, it don’t include Desktop, only support serial console.
Download link:
Baidu link: https://pan.baidu.com/s/1JD3Yn9TYRd_nR8A1AJpqdQ Pincode：fv8e
how to use :