diff --git a/hw/riscv/sifive_u.c b/hw/riscv/sifive_u.c
index 698637e8e1..89cccd7fd5 100644
--- a/hw/riscv/sifive_u.c
+++ b/hw/riscv/sifive_u.c
@@ -95,9 +95,9 @@ static void create_fdt(SiFiveUState *s, const MemMapEntry *memmap,
     int cpu;
     uint32_t *cells;
     char *nodename;
-    char ethclk_names[] = "pclk\0hclk";
     uint32_t plic_phandle, prci_phandle, gpio_phandle, phandle = 1;
     uint32_t hfclk_phandle, rtcclk_phandle, phy_phandle;
+    static const char * const ethclk_names[2] = { "pclk", "hclk" };
 
     if (ms->dtb) {
         fdt = s->fdt = load_device_tree(ms->dtb, &s->fdt_size);
@@ -412,8 +412,8 @@ static void create_fdt(SiFiveUState *s, const MemMapEntry *memmap,
     qemu_fdt_setprop_cell(fdt, nodename, "interrupts", SIFIVE_U_GEM_IRQ);
     qemu_fdt_setprop_cells(fdt, nodename, "clocks",
         prci_phandle, PRCI_CLK_GEMGXLPLL, prci_phandle, PRCI_CLK_GEMGXLPLL);
-    qemu_fdt_setprop(fdt, nodename, "clock-names", ethclk_names,
-        sizeof(ethclk_names));
+    qemu_fdt_setprop_string_array(fdt, nodename, "clock-names",
+        (char **)&ethclk_names, ARRAY_SIZE(ethclk_names));
     qemu_fdt_setprop(fdt, nodename, "local-mac-address",
         s->soc.gem.conf.macaddr.a, ETH_ALEN);
     qemu_fdt_setprop_cell(fdt, nodename, "#address-cells", 1);