diff --git a/machine/fdt.c b/machine/fdt.c
index d5beda1..fee3ae9 100644
--- a/machine/fdt.c
+++ b/machine/fdt.c
@@ -651,8 +651,12 @@ static bool hart_filter_mask(const struct hart_filter *filter)
 {
   if (filter->mmu_type == NULL) return true;
   if (strcmp(filter->status, "okay")) return true;
+#if __riscv_xlen == 32
+  if (!strcmp(filter->mmu_type, "riscv,sv32")) return false;
+#else
   if (!strcmp(filter->mmu_type, "riscv,sv39")) return false;
   if (!strcmp(filter->mmu_type, "riscv,sv48")) return false;
+#endif
   printm("hart_filter_mask saw unknown hart type: status=\"%s\", mmu_type=\"%s\"\n",
          filter->status, filter->mmu_type);
   return true;