diff --git a/hw/sun4m.c b/hw/sun4m.c
index 95c505821b..41730bc7a8 100644
--- a/hw/sun4m.c
+++ b/hw/sun4m.c
@@ -1030,9 +1030,7 @@ static void sun4m_hw_init(const struct sun4m_hwdef *hwdef, ram_addr_t RAM_size,
     if (kernel_cmdline) {
         fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_CMDLINE, CMDLINE_ADDR);
         pstrcpy_targphys("cmdline", CMDLINE_ADDR, TARGET_PAGE_SIZE, kernel_cmdline);
-        fw_cfg_add_bytes(fw_cfg, FW_CFG_CMDLINE_DATA,
-                         (uint8_t*)strdup(kernel_cmdline),
-                         strlen(kernel_cmdline) + 1);
+        fw_cfg_add_string(fw_cfg, FW_CFG_CMDLINE_DATA, kernel_cmdline);
         fw_cfg_add_i32(fw_cfg, FW_CFG_CMDLINE_SIZE,
                        strlen(kernel_cmdline) + 1);
     } else {
@@ -1676,9 +1674,7 @@ static void sun4d_hw_init(const struct sun4d_hwdef *hwdef, ram_addr_t RAM_size,
     if (kernel_cmdline) {
         fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_CMDLINE, CMDLINE_ADDR);
         pstrcpy_targphys("cmdline", CMDLINE_ADDR, TARGET_PAGE_SIZE, kernel_cmdline);
-        fw_cfg_add_bytes(fw_cfg, FW_CFG_CMDLINE_DATA,
-                         (uint8_t*)strdup(kernel_cmdline),
-                         strlen(kernel_cmdline) + 1);
+        fw_cfg_add_string(fw_cfg, FW_CFG_CMDLINE_DATA, kernel_cmdline);
     } else {
         fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_CMDLINE, 0);
     }
@@ -1878,9 +1874,7 @@ static void sun4c_hw_init(const struct sun4c_hwdef *hwdef, ram_addr_t RAM_size,
     if (kernel_cmdline) {
         fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_CMDLINE, CMDLINE_ADDR);
         pstrcpy_targphys("cmdline", CMDLINE_ADDR, TARGET_PAGE_SIZE, kernel_cmdline);
-        fw_cfg_add_bytes(fw_cfg, FW_CFG_CMDLINE_DATA,
-                         (uint8_t*)strdup(kernel_cmdline),
-                         strlen(kernel_cmdline) + 1);
+        fw_cfg_add_string(fw_cfg, FW_CFG_CMDLINE_DATA, kernel_cmdline);
     } else {
         fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_CMDLINE, 0);
     }
diff --git a/hw/sun4u.c b/hw/sun4u.c
index cb75d03278..d36acde545 100644
--- a/hw/sun4u.c
+++ b/hw/sun4u.c
@@ -886,9 +886,7 @@ static void sun4uv_init(MemoryRegion *address_space_mem,
     if (kernel_cmdline) {
         fw_cfg_add_i32(fw_cfg, FW_CFG_CMDLINE_SIZE,
                        strlen(kernel_cmdline) + 1);
-        fw_cfg_add_bytes(fw_cfg, FW_CFG_CMDLINE_DATA,
-                         (uint8_t*)strdup(kernel_cmdline),
-                         strlen(kernel_cmdline) + 1);
+        fw_cfg_add_string(fw_cfg, FW_CFG_CMDLINE_DATA, kernel_cmdline);
     } else {
         fw_cfg_add_i32(fw_cfg, FW_CFG_CMDLINE_SIZE, 0);
     }