--- /dev/null
+--- a/arch/mips/ath79/machtypes.h
++++ b/arch/mips/ath79/machtypes.h
+@@ -51,6 +51,7 @@ enum ath79_mach_type {
+ ATH79_MACH_RB_493, /* Mikrotik RouterBOARD 493/493AH */
+ ATH79_MACH_RB_493G, /* Mikrotik RouterBOARD 493G */
+ ATH79_MACH_RB_750, /* MikroTik RouterBOARD 750 */
++ ATH79_MACH_RB_750G_R3, /* MikroTik RouterBOARD 750GL */
+ ATH79_MACH_RW2458N, /* Redwave RW2458N */
+ ATH79_MACH_TEW_632BRP, /* TRENDnet TEW-632BRP */
+ ATH79_MACH_TEW_673GRU, /* TRENDnet TEW-673GRU */
+--- 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)