diff --git a/hw/riscv/sifive_u.c b/hw/riscv/sifive_u.c
index b139824aab..b40a4767e2 100644
--- a/hw/riscv/sifive_u.c
+++ b/hw/riscv/sifive_u.c
@@ -287,7 +287,8 @@ static void create_fdt(SiFiveUState *s, const MemMapEntry *memmap,
     qemu_fdt_setprop_cells(fdt, nodename, "reg",
         0x0, memmap[SIFIVE_U_DEV_PLIC].base,
         0x0, memmap[SIFIVE_U_DEV_PLIC].size);
-    qemu_fdt_setprop_cell(fdt, nodename, "riscv,ndev", 0x35);
+    qemu_fdt_setprop_cell(fdt, nodename, "riscv,ndev",
+                          SIFIVE_U_PLIC_NUM_SOURCES - 1);
     qemu_fdt_setprop_cell(fdt, nodename, "phandle", plic_phandle);
     plic_phandle = qemu_fdt_get_phandle(fdt, nodename);
     g_free(cells);