I have ubuntu and windows on my computer, why does the screen go black when I start ubuntu, unless I start it from recover mode？

My English is not good, if my unskilled expression offends you, please forgive me

Ubuntu 20.04 windows10 ThinkPad E14

grub 'Ubuntu'：

setparams 'Ubuntu'
        recordfail
        load_video
        gfxmode $linux_gfx_mode
        insmod gzio
        if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
        insmod part_gpt
        insmod ext2
        set root='hd0,gpt3'
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt3 --hint-efi=hd0,gpt3 --hint-baremetal=ahci0,gpt3 a8beab09-a9e6-41ac-a2a1-5980318e7ea7
        else
          search --no-floppy --fs-uuid --set=root a8beab09-a9e6-41ac-a2a1-5980318e7ea7
        fi
        linux        /boot/vmlinuz-5.11.0-43-generic root=UUID=a8beab09-a9e6-41ac-a2a1-5980318e7ea7 ro quiet splash $vt_handoff
        initrd        /boot/initrd.img-5.11.0-43-generic

grub 'Ubuntu, with Linux 5.11.0-43-generic (recovery mode)'

setparams 'Ubuntu, with Linux 5.11.0-43-generic (recovery mode)'
        recordfail
        load_video
        insmod gzio
        if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
        insmod part_gpt
        insmod ext2
        set root='hd0,gpt3'
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt3 --hint-efi=hd0,gpt3 --hint-baremetal=ahci0,gpt3 a8beab09-a9e6-41ac-a2a1-5980318e7ea7
        else
          search --no-floppy --fs-uuid --set=root a8beab09-a9e6-41ac-a2a1-5980318e7ea7
        fi
        echo         'Loading Linux 5.11.0-43-generic ...'
        linux        /boot/vmlinuz-5.11.0-43-generic root=UUID=a8beab09-a9e6-41ac-a2a1-5980318e7ea7 ro recovery dis_ucode_ldr
        echo         'Loading initial ramdisk ...'
        initrd        /boot/initrd.img-5.11.0-43-generic

1. The entry 'Ubuntu (recover mode)' work normally, and my laptop's hdmi work normally.
2. The entry 'Ubuntu' shows black screen.
3. The entry 'Ubuntu' can start up successfully if I add 'nomodeset' after 'splash', but the laptop's hdmi can not work.

So, how can I start Ubuntu successfully and the hdmi work normally?

Why does the recover mode look normal? Can I always use recovery mode instead of 'Ubuntu'? Does this cause any problems?

It sounds like you might have a graphic card configuration not supported by the 20.04 kernel you are running (5.11.0-43). Your options are:

1. Update to the latest 20.04 kernel using: sudo apt update && sudo apt dist-upgrade && sudo apt autoremove
2. reboot and see if it fixed the problem. You can run the following to get your kernel version: uname -r
3. If you are still having issues, there are two options left:

• Upgrade to or install Ubuntu 21.10 and run the above APT instructions to get on the latest stable kernel for 21.10 (it's 5.13.0-22 as of today). 21.10 may have support for a newer kernel than 20.04. Double check this version against what you get in uname -r after running a dist-upgrade.

• Manually update your kernel to v5.15.11 (latest stable as of today). This is a bit risky as it may cause stability issues with your Ubuntu version or software installed. The APT method above is the best way to ensure you get the latest tested kernel for your version of Ubuntu. If you want to try to install the latest kernel manually, see this website for instructions how to get it done: https://ostechnix.com/different-ways-to-update-linux-kernel-for-ubuntu/