diff --git a/src/Makefile b/src/Makefile
index be5c7fda6..6367b13ea 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -26,6 +26,7 @@ PRINTF		:= printf
 PERL		:= perl
 PYTHON		:= python
 TRUE		:= true
+TRUNCATE	:= truncate
 CC		= $(CROSS_COMPILE)gcc
 CPP		= $(CC) -E
 AS		= $(CROSS_COMPILE)as
diff --git a/src/arch/riscv/Makefile.sbi b/src/arch/riscv/Makefile.sbi
index 2546366b2..d748ef42e 100644
--- a/src/arch/riscv/Makefile.sbi
+++ b/src/arch/riscv/Makefile.sbi
@@ -15,3 +15,10 @@ LDSCRIPT	= arch/riscv/scripts/sbi.lds
 #
 MEDIA		+= sbi
 MEDIA		+= lkrn
+
+# Padded flash device images (e.g. for QEMU's -pflash option)
+#
+NON_AUTO_MEDIA	+= pf32
+%.pf32 : %.sbi $(MAKEDEPS)
+	$(Q)$(CP) $< $@
+	$(Q)$(TRUNCATE) -s 32M $@