boot – Ubuntu 20.04 and 21.04 black screen with AMD A8-7680 with Radeon™ R7 Series

Fresh install Ubuntu 20.04 or 21.04. Wasn’t able to install unless safe graphics mode selected. After install hangs at final stage of booting with black screen.

AMD A8-7680 processor with build in Radeon™ R7 Series graphics.

Installing oem kernel

sudo apt install linux-oem-20.04b

And booting older kernel doesn’t help.

With grub nomodeset boots OK, but works in 1024×768 resolution only.

GRUB_CMDLINE_LINUX_DEFAULT="nomodeset"

Proprietary R7 driver for 20.04 is unavailable.
Downgrading to 18.04 is not really working, because it doesn’t pass audio to HDMI anymore. Also it is in-laws computer and they live in another country I’m don’t feel safe to leave it with old kernel, with possibility to have dead computer after any kernel update.

I have been using Ubuntu desktop and server software for 15 years,thanks developers and community. System improved greatly over those years. Unfortunately progress always comes with costs, especially for those with newer or older hardware. Computer is just a couple of years old. There are lots of desktop and laptop computers with this type of processors and graphics cards. Problem is not trivial and wouldn’t disappear itself in near future.