diff --git a/arch/arm/include/asm/arch-rockchip/sys_proto.h b/arch/arm/include/asm/arch-rockchip/sys_proto.h
index 905c774..de5a8f1 100644
--- a/arch/arm/include/asm/arch-rockchip/sys_proto.h
+++ b/arch/arm/include/asm/arch-rockchip/sys_proto.h
@@ -6,8 +6,4 @@
 #ifndef _ASM_ARCH_SYS_PROTO_H
 #define _ASM_ARCH_SYS_PROTO_H
 
-
-/* provided to defeat compiler optimisation in board_init_f() */
-void gru_dummy_function(int i);
-
 #endif /* _ASM_ARCH_SYS_PROTO_H */
diff --git a/arch/arm/mach-rockchip/rk3399-board-spl.c b/arch/arm/mach-rockchip/rk3399-board-spl.c
index e632527..cb481c5 100644
--- a/arch/arm/mach-rockchip/rk3399-board-spl.c
+++ b/arch/arm/mach-rockchip/rk3399-board-spl.c
@@ -57,6 +57,11 @@
 {
 }
 
+__weak int board_early_init_f(void)
+{
+	return 0;
+}
+
 __weak int arch_cpu_init(void)
 {
 	return 0;
@@ -70,20 +75,6 @@
 #ifdef CONFIG_DEBUG_UART
 	debug_uart_init();
 
-# ifdef CONFIG_TARGET_CHROMEBOOK_BOB
-	int sum, i;
-
-	/*
-	 * Add a delay and ensure that the compiler does not optimise this out.
-	 * This is needed since the power rails tail a while to turn on, and
-	 * we get garbage serial output otherwise.
-	 */
-	sum = 0;
-	for (i = 0; i < 150000; i++)
-		sum += i;
-	gru_dummy_function(sum);
-#endif /* CONFIG_TARGET_CHROMEBOOK_BOB */
-
 	/*
 	 * Debug UART can be used from here if required:
 	 *
@@ -95,6 +86,7 @@
 	debug("U-Boot SPL board init\n");
 #endif
 
+	board_early_init_f();
 	arch_cpu_init();
 
 	ret = spl_early_init();
diff --git a/board/google/gru/gru.c b/board/google/gru/gru.c
index b116b1a..c2895e1 100644
--- a/board/google/gru/gru.c
+++ b/board/google/gru/gru.c
@@ -10,7 +10,28 @@
 	return 0;
 }
 
+#ifdef CONFIG_SPL_BUILD
 /* provided to defeat compiler optimisation in board_init_f() */
 void gru_dummy_function(int i)
 {
 }
+
+int board_early_init_f(void)
+{
+# ifdef CONFIG_TARGET_CHROMEBOOK_BOB
+	int sum, i;
+
+	/*
+	 * Add a delay and ensure that the compiler does not optimise this out.
+	 * This is needed since the power rails tail a while to turn on, and
+	 * we get garbage serial output otherwise.
+	 */
+	sum = 0;
+	for (i = 0; i < 150000; i++)
+		sum += i;
+	gru_dummy_function(sum);
+#endif /* CONFIG_TARGET_CHROMEBOOK_BOB */
+
+	return 0;
+}
+#endif