Notes on porting the NetBSD to ACube Sam4x0 boards

There is an ongoing project to port NetBSD to ACube Systems Sam460ex board.

Support for PPC 440 cores

Support for PowerPC 440 CPU and AMCC 460EX SoC was added to NetBSD in June 2026. Stress tests conducted so far have shown that the system is stable and performs acceptably.

Sam460ex support

The porting effort now focuses on adding support for the specific hardware features of the Sam460ex board.

Board already boots NetBSD to multi-user mode, but not all hardware features and configurations are fully supported yet.

Firmware

Sam4x0 boards use U-Boot firmware, which is stored in a Flash chip.

For development work it is possible to boot the NetBSD kernel directly from U-Boot via TFTP and automatically mount root file system from NFS server:

setenv serverip 192.168.100.1
setenv ipaddr 192.168.100.2

setenv bootargs root=emac0

tftp 0x4000000 netbsd.gz.ub
tftp 0x5000000 canyonlands.dtb
bootm 0x4000000 - 0x5000000