How much of the u-boot and Linux kernel binaries which ship with the Pinebook Pro (or are used in the images/installers linked from the wiki) is already integra

How much of the u-boot and Linux kernel binaries which ship with the Pinebook Pro (or are used in the images/installers linked from the wiki) is already integrated into the mainline or upstream of each of these projects? If not much, where can I find information about their plans to contribute their changes? Are there any plans for UEFI support to be added to the Pinebook Pro so that it can easily boot installers that already exist for 64 bit ARM Linux distributions?