diff --git a/headers/posix/termios.h b/headers/posix/termios.h
index 2f843111aa..3d590e67ed 100644
--- a/headers/posix/termios.h
+++ b/headers/posix/termios.h
@@ -9,21 +9,25 @@
 #include <sys/types.h>
 
 
-typedef __haiku_uint32 tcflag_t;
-typedef unsigned char speed_t;
+typedef __haiku_uint16 tcflag_t;
+typedef __haiku_uint32 speed_t;
 typedef unsigned char cc_t;
 
 #define NCCS	11		/* number of control characters */
 
 struct termios {
-	tcflag_t	c_iflag;	/* input modes */
-	tcflag_t	c_oflag;	/* output modes */
-	tcflag_t	c_cflag;	/* control modes */
-	tcflag_t	c_lflag;	/* local modes */
-	char		c_line;		/* line discipline */
-	speed_t		c_ispeed;	/* custom input baudrate */
-	speed_t		c_ospeed;	/* custom output baudrate */
-	cc_t		c_cc[NCCS];	/* control characters */
+	tcflag_t		c_iflag;			/* input modes */
+	tcflag_t		c_ispeed;			/* input baudrate */
+	tcflag_t		c_oflag;			/* output modes */
+	tcflag_t		c_ospeed;			/* output baudrate */
+	tcflag_t		c_cflag;			/* control modes */
+	tcflag_t		c_ispeed_high;		/* high word of input baudrate */
+	tcflag_t		c_lflag;			/* local modes */
+	tcflag_t		c_ospeed_high;		/* high word of output baudrate */
+	char			c_line;				/* line discipline */
+	unsigned char	_padding;		/* unused */
+	unsigned char	_padding2;		/* unused */
+	cc_t			c_cc[NCCS];			/* control characters */
 };
 
 /* control characters */
diff --git a/src/add-ons/kernel/drivers/ports/usb_serial/SerialDevice.cpp b/src/add-ons/kernel/drivers/ports/usb_serial/SerialDevice.cpp
index 8056983060..6000e0c99d 100644
--- a/src/add-ons/kernel/drivers/ports/usb_serial/SerialDevice.cpp
+++ b/src/add-ons/kernel/drivers/ports/usb_serial/SerialDevice.cpp
@@ -160,10 +160,11 @@ SerialDevice::SetModes(struct termios *tios)
 	TRACE_FUNCRES(trace_termios, tios);
 
 	uint8 baud = tios->c_cflag & CBAUD;
-	int32 speed = baud_index_to_speed(baud);
-	if (speed < 0) {
-		baud = CBAUD;
-		speed = tios->c_ospeed;
+	int32 speed;
+	if (baud == CBAUD) {
+		speed = tios->c_ospeed + (tios->c_ospeed_high << 16);
+	} else {
+		speed = baud_index_to_speed(baud);
 	}
 
 	// update our master config in full
diff --git a/src/add-ons/kernel/drivers/ports/usb_serial/Tracing.cpp b/src/add-ons/kernel/drivers/ports/usb_serial/Tracing.cpp
index be3b3684fb..dfee837ae9 100644
--- a/src/add-ons/kernel/drivers/ports/usb_serial/Tracing.cpp
+++ b/src/add-ons/kernel/drivers/ports/usb_serial/Tracing.cpp
@@ -106,17 +106,18 @@ void
 trace_termios(struct termios *tios)
 {
 	TRACE("struct termios:\n"
-		"\tc_iflag:  0x%08x\n"
-		"\tc_oflag:  0x%08x\n"
-		"\tc_cflag:  0x%08x\n"
-		"\tc_lflag:  0x%08x\n"
-		"\tc_line:   0x%08x\n"
-		"\tc_ispeed: 0x%08x\n"
-		"\tc_ospeed: 0x%08x\n"
+		"\tc_iflag:          0x%04x\n"
+		"\tc_oflag:          0x%04x\n"
+		"\tc_cflag:          0x%04x\n"
+		"\tc_lflag:          0x%04x\n"
+		"\tc_line:           0x%04x\n"
+		"\tc_ispeed:         %u\n"
+		"\tc_ospeed:         %u\n"
 		"\tc_cc[0x%02x, 0x%02x, 0x%02x, 0x%02x, 0x%02x, 0x%02x, 0x%02x, 0x%02x, 0x%02x, 0x%02x, 0x%02x]\n",
 		tios->c_iflag, tios->c_oflag, tios->c_cflag, tios->c_lflag,
 		tios->c_line,
-		tios->c_ispeed, tios->c_ospeed,
+		tios->c_ispeed + ((uint32_t)tios->c_ispeed_high << 16),
+		tios->c_ospeed + (tios->c_ospeed_high << 16),
 		tios->c_cc[0], tios->c_cc[1], tios->c_cc[2], tios->c_cc[3],
 		tios->c_cc[4], tios->c_cc[5], tios->c_cc[6], tios->c_cc[7],
 		tios->c_cc[8], tios->c_cc[9], tios->c_cc[10]);
diff --git a/src/add-ons/kernel/generic/tty/module.cpp b/src/add-ons/kernel/generic/tty/module.cpp
index d9f501251c..830400e86e 100644
--- a/src/add-ons/kernel/generic/tty/module.cpp
+++ b/src/add-ons/kernel/generic/tty/module.cpp
@@ -28,17 +28,19 @@ dump_tty_settings(struct tty_settings& settings)
 	kprintf("  session_id:   %" B_PRId32 "\n", settings.session_id);
 
 	kprintf("  termios:\n");
-	kprintf("    c_iflag:    0x%08" B_PRIx32 "\n", settings.termios.c_iflag);
-	kprintf("    c_oflag:    0x%08" B_PRIx32 "\n", settings.termios.c_oflag);
-	kprintf("    c_cflag:    0x%08" B_PRIx32 "\n", settings.termios.c_cflag);
-	kprintf("    c_lflag:    0x%08" B_PRIx32 "\n", settings.termios.c_lflag);
-	kprintf("    c_line:     %d\n", settings.termios.c_line);
-	kprintf("    c_ispeed:   %u\n", settings.termios.c_ispeed);
-	kprintf("    c_ospeed:   %u\n", settings.termios.c_ospeed);
+	kprintf("    c_iflag:          0x%08" B_PRIx32 "\n", settings.termios.c_iflag);
+	kprintf("    c_oflag:          0x%08" B_PRIx32 "\n", settings.termios.c_oflag);
+	kprintf("    c_cflag:          0x%08" B_PRIx32 "\n", settings.termios.c_cflag);
+	kprintf("    c_lflag:          0x%08" B_PRIx32 "\n", settings.termios.c_lflag);
+	kprintf("    c_line:           %d\n", settings.termios.c_line);
+	kprintf("    c_ispeed:         %u\n", settings.termios.c_ispeed
+		+ ((uint32_t)settings.termios.c_ispeed_high << 16));
+	kprintf("    c_ospeed:         %u\n", settings.termios.c_ospeed
+		+ ((uint32_t)settings.termios.c_ospeed_high << 16));
 	for (int i = 0; i < NCCS; i++)
-		kprintf("    c_cc[%02d]:   %d\n", i, settings.termios.c_cc[i]);
+		kprintf("    c_cc[%02d]:       %d\n", i, settings.termios.c_cc[i]);
 
-	kprintf("  wsize:        %u x %u c, %u x %u pxl\n",
+	kprintf("  wsize:              %u x %u c, %u x %u pxl\n",
 		settings.window_size.ws_row, settings.window_size.ws_col,
 		settings.window_size.ws_xpixel, settings.window_size.ws_ypixel);
 }
diff --git a/src/add-ons/kernel/generic/tty/tty.cpp b/src/add-ons/kernel/generic/tty/tty.cpp
index ddae54a01c..dea650b6e8 100644
--- a/src/add-ons/kernel/generic/tty/tty.cpp
+++ b/src/add-ons/kernel/generic/tty/tty.cpp
@@ -760,8 +760,10 @@ reset_termios(struct termios& termios)
 	termios.c_cflag = B19200 | CS8 | CREAD | HUPCL;
 		// enable receiver, hang up on last close
 	termios.c_lflag = ECHO | ISIG | ICANON;
-	termios.c_ispeed = B19200;
-	termios.c_ospeed = B19200;
+	termios.c_ispeed = 0;
+	termios.c_ospeed = 0;
+	termios.c_ispeed_high = 0;
+	termios.c_ospeed_high = 0;
 
 	// control characters
 	termios.c_cc[VINTR] = CTRL('C');
diff --git a/src/libs/bsd/termios.c b/src/libs/bsd/termios.c
index 1049aeea6a..0513b33f25 100644
--- a/src/libs/bsd/termios.c
+++ b/src/libs/bsd/termios.c
@@ -11,12 +11,14 @@
 int
 cfsetspeed(struct termios *termios, speed_t speed)
 {
-	/* Custom speed values are stored in c_ispeed and c_ospeed.
+	/* Custom values are stored in two parts for ABI compatibility reasons.
 	 * Standard values are inlined in c_cflag. */
 	if (speed > B31250) {
 		termios->c_cflag |= CBAUD;
-		termios->c_ispeed = speed;
-		termios->c_ospeed = speed;
+		termios->c_ospeed = speed & 0xFFFF;
+		termios->c_ospeed_high = speed >> 16;
+		termios->c_ispeed = termios->c_ospeed;
+		termios->c_ispeed_high = termios->c_ospeed_high;
 		return 0;
 	}
 
diff --git a/src/system/libroot/posix/termios.c b/src/system/libroot/posix/termios.c
index ce0ebed5f4..8b2e949fea 100644
--- a/src/system/libroot/posix/termios.c
+++ b/src/system/libroot/posix/termios.c
@@ -106,7 +106,7 @@ speed_t
 cfgetispeed(const struct termios *termios)
 {
 	if ((termios->c_cflag & CBAUD) == CBAUD)
-		return termios->c_ispeed;
+		return termios->c_ispeed + ((uint32_t)termios->c_ispeed_high << 16);
 
 	return termios->c_cflag & CBAUD;
 }
@@ -121,7 +121,8 @@ cfsetispeed(struct termios *termios, speed_t speed)
 	detected only when the tcsetattr() function is called */
 	if (speed > B31250) {
 		termios->c_cflag |= CBAUD;
-		termios->c_ispeed = speed;
+		termios->c_ispeed = speed & 0xFFFF;
+		termios->c_ispeed_high = speed >> 16;
 		return 0;
 	}
 
@@ -135,7 +136,7 @@ speed_t
 cfgetospeed(const struct termios *termios)
 {
 	if ((termios->c_cflag & CBAUD) == CBAUD)
-		return termios->c_ospeed;
+		return termios->c_ospeed + ((uint32_t)termios->c_ospeed_high << 16);
 
 	return termios->c_cflag & CBAUD;
 }
@@ -147,7 +148,8 @@ cfsetospeed(struct termios *termios, speed_t speed)
 	/* Check for custom speed values (see above) */
 	if (speed > B31250) {
 		termios->c_cflag |= CBAUD;
-		termios->c_ospeed = speed;
+		termios->c_ospeed = speed & 0xFFFF;
+		termios->c_ospeed_high = speed >> 16;
 		return 0;
 	}