+--- a/arch/mips/ath79/prom.c
++++ b/arch/mips/ath79/prom.c
+@@ -180,6 +180,9 @@ void __init prom_init(void)
+ ath79_prom_append_cmdline("board", env);
+ }
+ }
++
++ if (strstr(arcs_cmdline, "board=750Gr3"))
++ ath79_prom_append_cmdline("console", "ttyS0,115200");
+ }
+
+ void __init prom_free_prom_memory(void)