diff --git a/include/grub/mips/yeeloong/serial.h b/include/grub/mips/yeeloong/serial.h
index 9390ea18a..bced102b6 100644
--- a/include/grub/mips/yeeloong/serial.h
+++ b/include/grub/mips/yeeloong/serial.h
@@ -19,6 +19,11 @@
#ifndef GRUB_MACHINE_SERIAL_HEADER
#define GRUB_MACHINE_SERIAL_HEADER 1
+#ifndef ASM_FILE
#define GRUB_MACHINE_SERIAL_PORTS { 0xbff003f8 }
+#else
+#define GRUB_MACHINE_SERIAL_PORT_HI 0xbff0
+#define GRUB_MACHINE_SERIAL_PORT_LO 0x03f8
+#endif
#endif
diff --git a/kern/mips/yeeloong/fwstart.S b/kern/mips/yeeloong/fwstart.S
new file mode 100644
index 000000000..5132d7584
--- /dev/null
+++ b/kern/mips/yeeloong/fwstart.S
@@ -0,0 +1,81 @@
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 2000,2001,2002,2003,2004,2005,2007,2008,2009,2010 Free Software Foundation, Inc.
+ *
+ * GRUB is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GRUB is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GRUB. If not, see .
+ */
+
+#include
+#include
+
+ .set noreorder
+ .set noat
+ .set nomacro
+
+ bal serial_hw_init
+ nop
+self:
+ b self
+ nop
+
+ /* Same as similarly named C function but in asm since
+ we need it early. */
+ /* In: none. Out: none. Clobbered: $t0, $t1, $a0. */
+serial_hw_init:
+ lui $t0, GRUB_MACHINE_SERIAL_PORT_HI
+
+ /* Turn off the interrupt. */
+ sb $zero, (GRUB_MACHINE_SERIAL_PORT_LO + UART_IER)($t0)
+
+ /* Set DLAB. */
+ ori $t1, $zero, UART_DLAB
+ sb $t1, (GRUB_MACHINE_SERIAL_PORT_LO + UART_LCR)($t0)
+
+ /* Set the baud rate 115200. */
+ ori $t1, $zero, 2
+ sb $t1, (GRUB_MACHINE_SERIAL_PORT_LO + UART_DLL)($t0)
+ sb $zero, (GRUB_MACHINE_SERIAL_PORT_LO + UART_DLH)($t0)
+
+ /* Set the line status. */
+ ori $t1, $zero, (UART_NO_PARITY | UART_8BITS_WORD | UART_1_STOP_BIT)
+ sb $t1, (GRUB_MACHINE_SERIAL_PORT_LO + UART_LCR)($t0)
+
+ /* Enable the FIFO. */
+ ori $t1, $zero, UART_ENABLE_FIFO_TRIGGER1
+ sb $t1, (GRUB_MACHINE_SERIAL_PORT_LO + UART_FCR)($t0)
+
+ /* Turn on DTR and RTS. */
+ ori $t1, $zero, UART_ENABLE_DTRRTS
+ sb $t1, (GRUB_MACHINE_SERIAL_PORT_LO + UART_MCR)($t0)
+
+ lui $t0, 0xbff0
+ addiu $t0, $t0, 0x03f8
+
+ /* Let message return to original caller. */
+ lui $a0, %hi(notification_string)
+ addiu $a0, $a0, %lo(notification_string)
+
+ /* Print message on serial console. */
+ /* In: $a0 = asciiz message. Out: none. Clobbered: $t0, $t1, $a0. */
+message:
+ lui $t0, GRUB_MACHINE_SERIAL_PORT_HI
+1:
+ lb $t1, 0($a0)
+ addiu $a0, $a0, 1
+ bne $t1, $zero, 1b
+ sb $t1, (GRUB_MACHINE_SERIAL_PORT_LO + UART_TX)($t0)
+ jr $ra
+ nop
+
+notification_string: .asciz "GRUB "