Black screen after selecting ubuntu in GRUB

[alirezaismyname]

Hello.
After installing Ukylin and after selecting Ubuntu in the GRUB menu, a black screen appears and nothing happens.
I have tested editing the entry and adding nomodeset at the end of the linux line or replacing quiet splash with nomodeset console=tty1 loglevel=7, but these methods were not effective.
GPU: Nvidia GeForce GTX 960M

[handsome-feng]

Hi, can you boot into multi-user mode by adding systemd.unit=multi-user.target to the linux line?

[alirezaismyname]

Sorry for my late reply, and thanks for your support.
Unfortunately, it doesn't work.

Ubuntu Kylin 20.04 LTS Pro

[alirezaismyname]

The problem has been fixed.
I used Boot-Repair on an Ubuntu Kylin live CD. I found it on this page.

I think it reinstalled grub. Now my grub looks like the default grub, and not like the customized UKylin version.
Therefore, maybe the problem is caused by the customized grub.

Thanks.