Index: head/stand/efi/include/efilib.h
===================================================================
--- head/stand/efi/include/efilib.h
+++ head/stand/efi/include/efilib.h
@@ -106,6 +106,7 @@
 void efi_time_init(void);
 void efi_time_fini(void);
 
+int parse_uefi_con_out(void);
 bool efi_cons_update_mode(void);
 EFI_STATUS efi_main(EFI_HANDLE Ximage, EFI_SYSTEM_TABLE* Xsystab);
 
Index: head/stand/efi/libefi/Makefile
===================================================================
--- head/stand/efi/libefi/Makefile
+++ head/stand/efi/libefi/Makefile
@@ -61,4 +61,9 @@
 # Handle FreeBSD specific %b and %D printf format specifiers
 CFLAGS+= ${FORMAT_EXTENSIONS}
 
+# Do not use TERM_EMU on arm and arm64 as it doesn't behave well with serial console
+.if ${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "aarch64"
+CFLAGS+= -DTERM_EMU
+.endif
+
 .include <bsd.lib.mk>
Index: head/stand/efi/libefi/efi_console.c
===================================================================
--- head/stand/efi/libefi/efi_console.c
+++ head/stand/efi/libefi/efi_console.c
@@ -30,6 +30,7 @@
 #include <efi.h>
 #include <efilib.h>
 #include <teken.h>
+#include <sys/reboot.h>
 
 #include "bootstrap.h"
 
@@ -38,6 +39,26 @@
 static SIMPLE_INPUT_INTERFACE		*conin;
 static EFI_SIMPLE_TEXT_INPUT_EX_PROTOCOL *coninex;
 
+static int mode;		/* Does ConOut have serial console? */
+
+static uint32_t utf8_left;
+static uint32_t utf8_partial;
+#ifdef TERM_EMU
+#define	DEFAULT_FGCOLOR EFI_LIGHTGRAY
+#define	DEFAULT_BGCOLOR EFI_BLACK
+
+#define	MAXARGS 8
+static int args[MAXARGS], argc;
+static int fg_c, bg_c, curx, cury;
+static int esc;
+
+void get_pos(int *x, int *y);
+void curs_move(int *_x, int *_y, int x, int y);
+static void CL(int);
+void HO(void);
+void end_term(void);
+#endif
+
 static tf_bell_t	efi_cons_bell;
 static tf_cursor_t	efi_text_cursor;
 static tf_putchar_t	efi_text_putchar;
@@ -447,6 +468,340 @@
 	return (CMD_OK);
 }
 
+#ifdef TERM_EMU
+/* Get cursor position. */
+void
+get_pos(int *x, int *y)
+{
+	*x = conout->Mode->CursorColumn;
+	*y = conout->Mode->CursorRow;
+}
+
+/* Move cursor to x rows and y cols (0-based). */
+void
+curs_move(int *_x, int *_y, int x, int y)
+{
+	conout->SetCursorPosition(conout, x, y);
+	if (_x != NULL)
+		*_x = conout->Mode->CursorColumn;
+	if (_y != NULL)
+		*_y = conout->Mode->CursorRow;
+}
+ 
+/* Clear internal state of the terminal emulation code. */
+void
+end_term(void)
+{
+	esc = 0;
+	argc = -1;
+}
+#endif
+
+static void
+efi_cons_rawputchar(int c)
+{
+	int i;
+	UINTN x, y;
+	conout->QueryMode(conout, conout->Mode->Mode, &x, &y);
+
+	if (c == '\t') {
+		int n;
+
+		n = 8 - ((conout->Mode->CursorColumn + 8) % 8);
+		for (i = 0; i < n; i++)
+			efi_cons_rawputchar(' ');
+	} else {
+#ifndef TERM_EMU
+		if (c == '\n')
+			efi_cons_efiputchar('\r');
+		efi_cons_efiputchar(c);
+#else
+		switch (c) {
+		case '\r':
+			curx = 0;
+			efi_cons_efiputchar('\r');
+			return;
+		case '\n':
+			efi_cons_efiputchar('\n');
+			efi_cons_efiputchar('\r');
+			cury++;
+			if (cury >= y)
+				cury--;
+			curx = 0;
+			return;
+		case '\b':
+			if (curx > 0) {
+				efi_cons_efiputchar('\b');
+				curx--;
+			}
+			return;
+		default:
+			efi_cons_efiputchar(c);
+			curx++;
+			if (curx > x-1) {
+				curx = 0;
+				cury++;
+			}
+			if (cury > y-1) {
+				curx = 0;
+				cury--;
+			}
+		}
+#endif
+	}
+	conout->EnableCursor(conout, TRUE);
+}
+
+#ifdef TERM_EMU
+/* Gracefully exit ESC-sequence processing in case of misunderstanding. */
+static void
+bail_out(int c)
+{
+	char buf[16], *ch;
+	int i;
+
+	if (esc) {
+		efi_cons_rawputchar('\033');
+		if (esc != '\033')
+			efi_cons_rawputchar(esc);
+		for (i = 0; i <= argc; ++i) {
+			sprintf(buf, "%d", args[i]);
+			ch = buf;
+			while (*ch)
+				efi_cons_rawputchar(*ch++);
+		}
+	}
+	efi_cons_rawputchar(c);
+	end_term();
+}
+
+/* Clear display from current position to end of screen. */
+static void
+CD(void)
+{
+	int i;
+	UINTN x, y;
+
+	get_pos(&curx, &cury);
+	if (curx == 0 && cury == 0) {
+		conout->ClearScreen(conout);
+		end_term();
+		return;
+	}
+
+	conout->QueryMode(conout, conout->Mode->Mode, &x, &y);
+	CL(0);  /* clear current line from cursor to end */
+	for (i = cury + 1; i < y-1; i++) {
+		curs_move(NULL, NULL, 0, i);
+		CL(0);
+	}
+	curs_move(NULL, NULL, curx, cury);
+	end_term();
+}
+
+/*
+ * Absolute cursor move to args[0] rows and args[1] columns
+ * (the coordinates are 1-based).
+ */
+static void
+CM(void)
+{
+	if (args[0] > 0)
+		args[0]--;
+	if (args[1] > 0)
+		args[1]--;
+	curs_move(&curx, &cury, args[1], args[0]);
+	end_term();
+}
+
+/* Home cursor (left top corner), also called from mode command. */
+void
+HO(void)
+{
+	argc = 1;
+	args[0] = args[1] = 1;
+	CM();
+}
+ 
+/* Clear line from current position to end of line */
+static void
+CL(int direction)
+{
+	int i, len;
+	UINTN x, y;
+	CHAR16 *line;
+
+	conout->QueryMode(conout, conout->Mode->Mode, &x, &y);
+	switch (direction) {
+	case 0:	/* from cursor to end */
+		len = x - curx + 1;
+		break;
+	case 1:	/* from beginning to cursor */
+		len = curx;
+		break;
+	case 2:	/* entire line */
+		len = x;
+		break;
+	default:	/* NOTREACHED */
+		__unreachable();
+	}
+ 
+	if (cury == y - 1)
+		len--;
+
+	line = malloc(len * sizeof (CHAR16));
+	if (line == NULL) {
+		printf("out of memory\n");
+		return;
+	}
+	for (i = 0; i < len; i++)
+		line[i] = ' ';
+	line[len-1] = 0;
+
+	if (direction != 0)
+		curs_move(NULL, NULL, 0, cury);
+ 
+	conout->OutputString(conout, line);
+	/* restore cursor position */
+	curs_move(NULL, NULL, curx, cury);
+	free(line);
+	end_term();
+}
+
+static void
+get_arg(int c)
+{
+	if (argc < 0)
+		argc = 0;
+	args[argc] *= 10;
+	args[argc] += c - '0';
+}
+#endif
+ 
+/* Emulate basic capabilities of cons25 terminal */
+static void
+efi_term_emu(int c)
+{
+#ifdef TERM_EMU
+	static int ansi_col[] = {
+		0, 4, 2, 6, 1, 5, 3, 7
+	};
+	int t, i;
+	EFI_STATUS status;
+ 
+	switch (esc) {
+	case 0:
+		switch (c) {
+		case '\033':
+			esc = c;
+			break;
+		default:
+			efi_cons_rawputchar(c);
+			break;
+		}
+		break;
+	case '\033':
+		switch (c) {
+		case '[':
+			esc = c;
+			args[0] = 0;
+			argc = -1;
+			break;
+		default:
+			bail_out(c);
+			break;
+		}
+		break;
+	case '[':
+		switch (c) {
+		case ';':
+			if (argc < 0)
+				argc = 0;
+			else if (argc + 1 >= MAXARGS)
+				bail_out(c);
+			else
+				args[++argc] = 0;
+			break;
+		case 'H':		/* ho = \E[H */
+			if (argc < 0)
+				HO();
+			else if (argc == 1)
+				CM();
+			else
+				bail_out(c);
+			break;
+		case 'J':		/* cd = \E[J */
+			if (argc < 0)
+				CD();
+			else
+				bail_out(c);
+			break;
+		case 'm':
+			if (argc < 0) {
+				fg_c = DEFAULT_FGCOLOR;
+				bg_c = DEFAULT_BGCOLOR;
+			}
+			for (i = 0; i <= argc; ++i) {
+				switch (args[i]) {
+				case 0:		/* back to normal */
+					fg_c = DEFAULT_FGCOLOR;
+					bg_c = DEFAULT_BGCOLOR;
+					break;
+				case 1:		/* bold */
+					fg_c |= 0x8;
+					break;
+				case 4:		/* underline */
+				case 5:		/* blink */
+					bg_c |= 0x8;
+					break;
+				case 7:		/* reverse */
+					t = fg_c;
+					fg_c = bg_c;
+					bg_c = t;
+					break;
+				case 22:	/* normal intensity */
+					fg_c &= ~0x8;
+					break;
+				case 24:	/* not underline */
+				case 25:	/* not blinking */
+					bg_c &= ~0x8;
+					break;
+				case 30: case 31: case 32: case 33:
+				case 34: case 35: case 36: case 37:
+					fg_c = ansi_col[args[i] - 30];
+					break;
+				case 39:	/* normal */
+					fg_c = DEFAULT_FGCOLOR;
+					break;
+				case 40: case 41: case 42: case 43:
+				case 44: case 45: case 46: case 47:
+					bg_c = ansi_col[args[i] - 40];
+					break;
+				case 49:	/* normal */
+					bg_c = DEFAULT_BGCOLOR;
+					break;
+				}
+			}
+			conout->SetAttribute(conout, EFI_TEXT_ATTR(fg_c, bg_c));
+			end_term();
+			break;
+		default:
+			if (isdigit(c))
+				get_arg(c);
+			else
+				bail_out(c);
+			break;
+		}
+		break;
+	default:
+		bail_out(c);
+		break;
+	}
+#else
+	efi_cons_rawputchar(c);
+#endif
+}
+
 bool
 efi_cons_update_mode(void)
 {
@@ -461,35 +816,58 @@
 		rows = 24;
 	}
 
-	if (buffer != NULL) {
-		if (tp.tp_row == rows && tp.tp_col == cols)
-			return (true);
-		free(buffer);
-	} else {
-		teken_init(&teken, &tf, NULL);
-	}
+	/*
+	 * When we have serial port listed in ConOut, use pre-teken emulator,
+	 * if built with.
+	 * The problem is, we can not output text on efi and comconsole when
+	 * efi also has comconsole bound. But then again, we need to have
+	 * terminal emulator for efi text mode to support the menu.
+	 * While teken is too expensive to be used on serial console, the
+	 * pre-teken emulator is light enough to be used on serial console.
+	 */
+	mode = parse_uefi_con_out();
+	if ((mode & RB_SERIAL) == 0) {
+		if (buffer != NULL) {
+			if (tp.tp_row == rows && tp.tp_col == cols)
+				return (true);
+			free(buffer);
+		} else {
+			teken_init(&teken, &tf, NULL);
+		}
 
-	tp.tp_row = rows;
-	tp.tp_col = cols;
-	buffer = malloc(rows * cols * sizeof(*buffer));
-	if (buffer == NULL)
-		return (false);
+		tp.tp_row = rows;
+		tp.tp_col = cols;
+		buffer = malloc(rows * cols * sizeof(*buffer));
+		if (buffer == NULL)
+			return (false);
 
-	teken_set_winsize(&teken, &tp);
-	a = teken_get_defattr(&teken);
+		teken_set_winsize(&teken, &tp);
+		a = teken_get_defattr(&teken);
 
-	snprintf(env, sizeof(env), "%d", a->ta_fgcolor);
-	env_setenv("teken.fg_color", EV_VOLATILE, env, efi_set_colors,
-	    env_nounset);
-	snprintf(env, sizeof(env), "%d", a->ta_bgcolor);
-	env_setenv("teken.bg_color", EV_VOLATILE, env, efi_set_colors,
-	    env_nounset);
+		snprintf(env, sizeof(env), "%d", a->ta_fgcolor);
+		env_setenv("teken.fg_color", EV_VOLATILE, env, efi_set_colors,
+		    env_nounset);
+		snprintf(env, sizeof(env), "%d", a->ta_bgcolor);
+		env_setenv("teken.bg_color", EV_VOLATILE, env, efi_set_colors,
+		    env_nounset);
 
-	for (int row = 0; row < rows; row++)
-		for (int col = 0; col < cols; col++) {
-			buffer[col + row * tp.tp_col].c = ' ';
-			buffer[col + row * tp.tp_col].a = *a;
+		for (int row = 0; row < rows; row++) {
+			for (int col = 0; col < cols; col++) {
+				buffer[col + row * tp.tp_col].c = ' ';
+				buffer[col + row * tp.tp_col].a = *a;
+			}
 		}
+	} else {
+#ifdef TERM_EMU
+		conout->SetAttribute(conout, EFI_TEXT_ATTR(DEFAULT_FGCOLOR,
+		    DEFAULT_BGCOLOR));
+		end_term();
+		get_pos(&curx, &cury);
+		curs_move(&curx, &cury, curx, cury);
+		fg_c = DEFAULT_FGCOLOR;
+		bg_c = DEFAULT_BGCOLOR;
+#endif
+	}
 
 	snprintf(env, sizeof (env), "%u", (unsigned)rows);
 	setenv("LINES", env, 1);
@@ -522,10 +900,108 @@
 	return (1);
 }
 
+static void
+input_partial(void)
+{
+	unsigned i;
+	uint32_t c;
+
+	if (utf8_left == 0)
+		return;
+
+	for (i = 0; i < sizeof(utf8_partial); i++) {
+		c = (utf8_partial >> (24 - (i << 3))) & 0xff;
+		if (c != 0)
+			efi_term_emu(c);
+	}
+	utf8_left = 0;
+	utf8_partial = 0;
+}
+
+static void
+input_byte(uint8_t c)
+{
+	if ((c & 0x80) == 0x00) {
+		/* One-byte sequence. */
+		input_partial();
+		efi_term_emu(c);
+		return;
+	}
+	if ((c & 0xe0) == 0xc0) {
+		/* Two-byte sequence. */
+		input_partial();
+		utf8_left = 1;
+		utf8_partial = c;
+		return;
+	}
+	if ((c & 0xf0) == 0xe0) {
+		/* Three-byte sequence. */
+		input_partial();
+		utf8_left = 2;
+		utf8_partial = c;
+		return;
+	}
+	if ((c & 0xf8) == 0xf0) {
+		/* Four-byte sequence. */
+		input_partial();
+		utf8_left = 3;
+		utf8_partial = c;
+		return;
+	}
+	if ((c & 0xc0) == 0x80) {
+		/* Invalid state? */
+		if (utf8_left == 0) {
+			efi_term_emu(c);
+			return;
+		}
+		utf8_left--;
+		utf8_partial = (utf8_partial << 8) | c;
+		if (utf8_left == 0) {
+			uint32_t v, u;
+			uint8_t b;
+
+			v = 0;
+			u = utf8_partial;
+			b = (u >> 24) & 0xff;
+			if (b != 0) {		/* Four-byte sequence */
+				v = b & 0x07;
+				b = (u >> 16) & 0xff;
+				v = (v << 6) | (b & 0x3f);
+				b = (u >> 8) & 0xff;
+				v = (v << 6) | (b & 0x3f);
+				b = u & 0xff;
+				v = (v << 6) | (b & 0x3f);
+			} else if ((b = (u >> 16) & 0xff) != 0) {
+				v = b & 0x0f;	/* Three-byte sequence */
+				b = (u >> 8) & 0xff;
+				v = (v << 6) | (b & 0x3f);
+				b = u & 0xff;
+				v = (v << 6) | (b & 0x3f);
+			} else if ((b = (u >> 8) & 0xff) != 0) {
+				v = b & 0x1f;	/* Two-byte sequence */
+				b = u & 0xff;
+				v = (v << 6) | (b & 0x3f);
+			}
+			/* Send unicode char directly to console. */
+			efi_cons_efiputchar(v);
+			utf8_partial = 0;
+		}
+		return;
+	}
+	/* Anything left is illegal in UTF-8 sequence. */
+	input_partial();
+	efi_term_emu(c);
+}
+
 void
 efi_cons_putchar(int c)
 {
 	unsigned char ch = c;
+
+	if ((mode & RB_SERIAL) != 0) {
+		input_byte(ch);
+		return;
+	}
 
 	if (buffer != NULL)
 		teken_input(&teken, &ch, sizeof (ch));
Index: head/stand/efi/loader/main.c
===================================================================
--- head/stand/efi/loader/main.c
+++ head/stand/efi/loader/main.c
@@ -688,7 +688,7 @@
  * ACPI name space to map the UID for the serial port to a port. The
  * latter is especially hard.
  */
-static int
+int
 parse_uefi_con_out(void)
 {
 	int how, rv;