I´ve just installed 20.04 on my laptop, replacing 19.10.
The USB installer process worked perfectly, but after rebooting, I´m getting a black screen right after the grub, with no text, and selecting recovery mode gets stuck on "loading initial ramdisk".
I have tried editing the boot parameters, removing quiet splash, and changing gfxmode $linux_gfx_mode for gfxmode text, to be able to see some kind of info at boot, but the black screen still persists.
Machine: DELL Inspiron 15 5567 AMD Radeon R7 M445 Graphics Intel i7 Processor
Dual boot Ubuntu 20.04 + Windows 10 (it was working fine with 19.10)
Bios: Uefi, security OFF.