(chroot) livecd tmp # emerge --ask sys-firmware/radeon-ucode

 * IMPORTANT: 13 news items need reading for repository 'gentoo'.
 * Use eselect news read to view new items.


These are the packages that would be merged, in order:

Calculating dependencies... done!
[ebuild  N     ] sys-firmware/radeon-ucode-20160628 
[blocks B      ] sys-kernel/linux-firmware[-savedconfig] ("sys-kernel/linux-firmware[-savedconfig]" is blocking sys-firmware/radeon-ucode-20160628)
[blocks B      ] sys-firmware/radeon-ucode ("sys-firmware/radeon-ucode" is blocking sys-kernel/linux-firmware-20160331)

 * Error: The above package list contains packages which cannot be
 * installed at the same time on the same system.

  (sys-kernel/linux-firmware-20160331:0/0::gentoo, installed) pulled in by
    sys-kernel/linux-firmware required by @selected

  (sys-firmware/radeon-ucode-20160628:0/0::gentoo, ebuild scheduled for merge) pulled in by
    sys-firmware/radeon-ucode


For more information about Blocked Packages, please refer to the following
section of the Gentoo Linux x86 Handbook (architecture is irrelevant):