diff --git a/docs/user-guide.md b/docs/user-guide.md
index f10a6f3..00feacc 100644
--- a/docs/user-guide.md
+++ b/docs/user-guide.md
@@ -330,6 +330,15 @@
 For a better understanding of these options, the ARM development platform memory
 map is explained in the [Firmware Design].
 
+#### ARM CSS platform specific build options
+
+*   `CSS_DETECT_PRE_1_7_0_SCP`: Boolean flag to detect SCP version
+    incompatibility. Version 1.7.0 of the SCP firmware made a non-backwards
+    compatible change to the MTL protocol, used for AP/SCP communication.
+    Trusted Firmware no longer supports earlier SCP versions. If this option is
+    set to 1 then Trusted Firmware will detect if an earlier version is in use.
+    Default is 1.
+
 
 ### Creating a Firmware Image Package
 
diff --git a/plat/arm/css/common/css_common.mk b/plat/arm/css/common/css_common.mk
index edbfe1e..1b0404b 100644
--- a/plat/arm/css/common/css_common.mk
+++ b/plat/arm/css/common/css_common.mk
@@ -53,3 +53,11 @@
 endif
 
 NEED_BL30		:=	yes
+
+# Enable option to detect whether the SCP ROM firmware in use predates version
+# 1.7.0 and therefore, is incompatible.
+CSS_DETECT_PRE_1_7_0_SCP	:=	1
+
+# Process CSS_DETECT_PRE_1_7_0_SCP flag
+$(eval $(call assert_boolean,CSS_DETECT_PRE_1_7_0_SCP))
+$(eval $(call add_define,CSS_DETECT_PRE_1_7_0_SCP))
diff --git a/plat/arm/css/common/css_scp_bootloader.c b/plat/arm/css/common/css_scp_bootloader.c
index c6d63f2..6cf1667 100644
--- a/plat/arm/css/common/css_scp_bootloader.c
+++ b/plat/arm/css/common/css_scp_bootloader.c
@@ -148,6 +148,24 @@
 	cmd_info_payload->checksum = checksum;
 
 	scp_boot_message_send(sizeof(*cmd_info_payload));
+#if CSS_DETECT_PRE_1_7_0_SCP
+	{
+		const uint32_t deprecated_scp_nack_cmd = 0x404;
+		uint32_t mhu_status;
+
+		VERBOSE("Detecting SCP version incompatibility\n");
+
+		mhu_status = mhu_secure_message_wait();
+		if (mhu_status == deprecated_scp_nack_cmd) {
+			ERROR("Detected an incompatible version of the SCP firmware.\n");
+			ERROR("Only versions from v1.7.0 onwards are supported.\n");
+			ERROR("Please update the SCP firmware.\n");
+			return -1;
+		}
+
+		VERBOSE("SCP version looks OK\n");
+	}
+#endif /* CSS_DETECT_PRE_1_7_0_SCP */
 	response = scp_boot_message_wait(sizeof(response));
 	scp_boot_message_end();