diff --git a/firmware/include/vboot_api.h b/firmware/include/vboot_api.h
index 860a5fc..fdb7615 100644
--- a/firmware/include/vboot_api.h
+++ b/firmware/include/vboot_api.h
@@ -735,15 +735,15 @@
  * platform-dependent font.  Should be able to handle newlines '\n' in the
  * string.  Firmware must support displaying at least 20 lines of text, where
  * each line may be at least 80 characters long.  If the firmware has its own
- * debug state, it may display it to the screen below this information.
+ * debug state, it may display it to the screen below this information if the
+ * full_info parameter is set.
  *
- * NOTE: This is what we currently display when TAB is pressed.  Some
- * information (HWID, recovery reason) is ours; some (CMOS breadcrumbs) is
- * platform-specific.  If we decide to soft-render the HWID string
- * (chrome-os-partner:3693), we'll need to maintain our own fonts, so we'll
- * likely display it via VbExDisplayImage() above.
+ * @param info_str	The debug string to display
+ * @param full_info	1 if firmware should append its own info, 0 if not
+ *
+ * @return VBERROR_SUCCESS or error code on error.
  */
-VbError_t VbExDisplayDebugInfo(const char *info_str);
+VbError_t VbExDisplayDebugInfo(const char *info_str, int full_info);
 
 /**
  * Write vendor data to read-only VPD
diff --git a/firmware/lib/vboot_display.c b/firmware/lib/vboot_display.c
index 49c5331..c709425 100644
--- a/firmware/lib/vboot_display.c
+++ b/firmware/lib/vboot_display.c
@@ -405,7 +405,7 @@
 
 	buf[DEBUG_INFO_SIZE - 1] = '\0';
 	VB2_DEBUG("[TAB] Debug Info:\n%s", buf);
-	return VbExDisplayDebugInfo(buf);
+	return VbExDisplayDebugInfo(buf, 1);
 }
 
 #define MAGIC_WORD_LEN 5
diff --git a/firmware/lib/vboot_ui.c b/firmware/lib/vboot_ui.c
index dea6e03..3fb2ce6 100644
--- a/firmware/lib/vboot_ui.c
+++ b/firmware/lib/vboot_ui.c
@@ -422,7 +422,7 @@
 		VB2_DEBUG("dev_disable_boot is set\n");
 		VbDisplayScreen(ctx,
 				VB_SCREEN_DEVELOPER_TO_NORM, 0, NULL);
-		VbExDisplayDebugInfo(dev_disable_msg);
+		VbExDisplayDebugInfo(dev_disable_msg, 0);
 
 		/* Ignore space in VbUserConfirms()... */
 		switch (VbUserConfirms(ctx, 0)) {
diff --git a/firmware/lib/vboot_ui_common.c b/firmware/lib/vboot_ui_common.c
index af9c495..b15bf29 100644
--- a/firmware/lib/vboot_ui_common.c
+++ b/firmware/lib/vboot_ui_common.c
@@ -35,7 +35,7 @@
 		      enum vb2_beep_type beep)
 {
 	if (print_msg)
-		VbExDisplayDebugInfo(print_msg);
+		VbExDisplayDebugInfo(print_msg, 0);
 	if (!log_msg)
 		log_msg = print_msg;
 	if (log_msg)
@@ -60,7 +60,7 @@
 	VB2_DEBUG("Legacy boot is disabled\n");
 	VbExDisplayDebugInfo("WARNING: Booting legacy BIOS has not been "
 			     "enabled. Refer to the developer-mode "
-			     "documentation for details.\n");
+			     "documentation for details.\n", 0);
 	vb2_error_beep(VB_BEEP_NOT_ALLOWED);
 }
 
diff --git a/firmware/lib/vboot_ui_menu.c b/firmware/lib/vboot_ui_menu.c
index 39b00d6..96a24e0 100644
--- a/firmware/lib/vboot_ui_menu.c
+++ b/firmware/lib/vboot_ui_menu.c
@@ -345,7 +345,7 @@
 	vb2_run_altfw(current_menu_idx + 1);
 	vb2_flash_screen(ctx);
 	VB2_DEBUG(no_legacy);
-	VbExDisplayDebugInfo(no_legacy);
+	VbExDisplayDebugInfo(no_legacy, 0);
 
 	return VBERROR_KEEP_LOOPING;
 }
@@ -775,7 +775,7 @@
 
 		/* Make sure user knows dev mode disabled */
 		if (disable_dev_boot)
-			VbExDisplayDebugInfo(dev_disable_msg);
+			VbExDisplayDebugInfo(dev_disable_msg, 0);
 
 		switch (key) {
 		case VB_BUTTON_VOL_DOWN_LONG_PRESS:
diff --git a/firmware/stub/vboot_api_stub.c b/firmware/stub/vboot_api_stub.c
index 599b80c..3363aa4 100644
--- a/firmware/stub/vboot_api_stub.c
+++ b/firmware/stub/vboot_api_stub.c
@@ -39,7 +39,7 @@
 	return VBERROR_SUCCESS;
 }
 
-VbError_t VbExDisplayDebugInfo(const char *info_str)
+VbError_t VbExDisplayDebugInfo(const char *info_str, int full_info)
 {
 	return VBERROR_SUCCESS;
 }
diff --git a/tests/vboot_display_tests.c b/tests/vboot_display_tests.c
index ef9d146..2c7691e 100644
--- a/tests/vboot_display_tests.c
+++ b/tests/vboot_display_tests.c
@@ -94,7 +94,7 @@
 	return mock_altfw_mask;
 }
 
-VbError_t VbExDisplayDebugInfo(const char *info_str)
+VbError_t VbExDisplayDebugInfo(const char *info_str, int full_info)
 {
 	strncpy(debug_info, info_str, sizeof(debug_info));
 	debug_info[sizeof(debug_info) - 1] = '\0';