Solved with changing boot mode to "Legacy support", with "UEFI first" option, in BIOS. Since the PC is still booting in UEFI mode with those settings, I really don't know why, just changing settings to act in a slightly different way (with same result), the graphic Grub works...
Here's my laptop specs, if it can help: Lenovo Z50-75 laptop MoBo: Lenovo Lancer 5B3 CPU: AMD A10-7300 GPU: Radeon R6 BIOS updated to A4CN43WW (V 2.12) version. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1863434 Title: 20.04 grub menu not visible To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1863434/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs