diff --git a/usr.sbin/bhyve/riscv/fdt.c b/usr.sbin/bhyve/riscv/fdt.c
--- a/usr.sbin/bhyve/riscv/fdt.c
+++ b/usr.sbin/bhyve/riscv/fdt.c
@@ -222,6 +222,7 @@
 	fdt_begin_node(fdt, node_name);
 	fdt_property_string(fdt, "compatible", "ns16550");
 	set_single_reg(fdt, uart_base, uart_size);
+	fdt_property_u32(fdt, "clock-frequency", 3686400);
 	fdt_property_u32(fdt, "interrupt-parent", aplic_phandle);
 	fdt_property_placeholder(fdt, "interrupts", 2 * sizeof(uint32_t),
 	    &interrupts);