I just committed a change to the armv7 bootloader that makes it pass the EFI memory map to the kernel. This will be used in the future to avoid stomping on memory used for the firmware, framebuffers etc. This change is incompatible with older versions of U-Boot. U-Boot 2017.03 that shipped with OpenBSD 6.1 is known to work, but if you're using an older version, you may need to upddate it.
The procedure to update U-Boot can be found in INSTALL.armv7 under "Install on systems without a supported miniroot". Cheers, Mark
