diff --git a/hal/sparcv8leon3/Makefile b/hal/sparcv8leon3/Makefile
index 319175da..814b9ee3 100644
--- a/hal/sparcv8leon3/Makefile
+++ b/hal/sparcv8leon3/Makefile
@@ -8,7 +8,6 @@
 
 include hal/sparcv8leon3/$(TARGET_SUBFAMILY)/Makefile
 
-CFLAGS := $(filter-out -mflat,$(CFLAGS)) # TODO: remove when kernel supports register windows
 CFLAGS += -Ihal/sparcv8leon3/$(TARGET_SUBFAMILY)
 
 OBJS += $(addprefix $(PREFIX_O)hal/$(TARGET_SUFF)/, cpu.o string.o interrupts.o exceptions.o _init.o _interrupts.o _traps.o)