New platform support in OpenBSD 5.4 includes "Octeon" for the Cavium Octeon MIPS-compatible processors via the Portwell CAM-0100 and Ubiquiti Networks EdgeRouter LITE. OpenBSD Beagle support now includes the OMAP3, OMAP4, and AM335x systems with ARM Cortex-A8/A9 ARM prcoessors. The newly supported ARM hardware includes the BeagleBoard C4, BeagleBoard xM, BeagleBone, BeagleBone Black, PandaBoard, and PandaBoard ES.
Following FreeBSD and other BSD platforms pulling in the Intel DRM/KMS driver from Linux, the same has been done for OpenBSD. The OpenBSD "inteldrm" driver is ported from the Linux 3.8 kernel and supports kernel mode-setting, now handles Sandy Bridge hardware and newer, and supports outputs like DisplayPort that previously weren't supported under OpenBSD.
Other hardware driver work includes vgafb/macppc supporting multiple virtual consoles, support for Elantech touchpads, and the vdsk driver now supports disks larger than two terabytes.
Some other OpenBSD 5.4 improvements include networking stack improvements, SSL inspection support in relayd, DHPCD and DHCLIENT improvements, performance improvements, and a variety of other enhancements.
More details on the new OpenBSD 5.4 release for various architectures can be found at OpenBSD.org.