diff --git a/Makefile b/Makefile
index 83aa038..34c1326 100644
--- a/Makefile
+++ b/Makefile
@@ -215,8 +215,9 @@
 # below uses CC itself.
 override ARCH := $(strip $(shell LC_ALL=C $(CC) $(CPPFLAGS) -E arch.h 2>/dev/null | grep -v '^\#' | grep '"' | cut -f 2 -d'"'))
 
-ifeq ($(ARCH), ppc)
-# There's no PCI port I/O support on PPC/PowerPC, yet.
+# PCI port I/O support is unimplemented on PPC/MIPS and unavailable on ARM.
+# Right now this means the drivers below only work on x86.
+ifneq ($(ARCH), x86)
 ifeq ($(CONFIG_NIC3COM), yes)
 UNSUPPORTED_FEATURES += CONFIG_NIC3COM=yes
 else