diff --git a/CMakeLists.txt b/CMakeLists.txt
index af45bd9b689..93d7c2aa6a3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -64,6 +64,7 @@ if(NOT LIBMGBA_ONLY)
 	set(BUILD_QT ON CACHE BOOL "Build Qt frontend")
 	set(BUILD_SDL ON CACHE BOOL "Build SDL frontend")
 	set(BUILD_LIBRETRO OFF CACHE BOOL "Build libretro core")
+	set(USE_DEVTERM OFF CACHE BOOL "Connect Game Boy core to DevTerm thermal printer")
 	if(APPLE)
 		set(BUILD_OPENEMU OFF CACHE BOOL "Build OpenEmu core")
 	endif()
@@ -987,11 +988,19 @@ if(BUILD_PYTHON)
 endif()
 
 if(BUILD_LIBRETRO)
+	include_directories(${CMAKE_CURRENT_SOURCE_DIR}/include/mgba-util/image)
 	file(GLOB RETRO_SRC ${CMAKE_CURRENT_SOURCE_DIR}/src/platform/libretro/*.c)
-	add_library(${BINARY_NAME}_libretro SHARED ${CORE_SRC} ${RETRO_SRC})
+	add_library(${BINARY_NAME}_libretro SHARED ${CORE_SRC} ${GB_SIO_SRC} ${UTIL_SRC} ${RETRO_SRC})
 	add_dependencies(${BINARY_NAME}_libretro ${BINARY_NAME}-version-info)
-	set_target_properties(${BINARY_NAME}_libretro PROPERTIES PREFIX "" COMPILE_DEFINITIONS "__LIBRETRO__;COLOR_16_BIT;COLOR_5_6_5;DISABLE_THREADING;MGBA_STANDALONE;${OS_DEFINES};${FUNCTION_DEFINES};MINIMAL_CORE=2")
-	target_link_libraries(${BINARY_NAME}_libretro ${OS_LIB})
+	set(LIBRETRO_DEFINES "__LIBRETRO__;COLOR_16_BIT;COLOR_5_6_5;DISABLE_THREADING;MGBA_STANDALONE;${OS_DEFINES};${FUNCTION_DEFINES};MINIMAL_CORE=2")
+	if (USE_PNG)
+		string(APPEND LIBRETRO_DEFINES ";USE_PNG")
+	endif()
+	if (USE_DEVTERM)
+		string(APPEND LIBRETRO_DEFINES ";USE_DEVTERM")
+	endif()
+	set_target_properties(${BINARY_NAME}_libretro PROPERTIES PREFIX "" COMPILE_DEFINITIONS "${LIBRETRO_DEFINES}")
+	target_link_libraries(${BINARY_NAME}_libretro ${DEPENDENCY_LIBS} ${OS_LIB})
 	if(MSVC)
 		install(TARGETS ${BINARY_NAME}_libretro RUNTIME DESTINATION ${LIBRETRO_LIBDIR} COMPONENT ${BINARY_NAME}_libretro)
 	else()
diff --git a/include/mgba/core/core.h b/include/mgba/core/core.h
index 7a6e89f5687..2b47c087acb 100644
--- a/include/mgba/core/core.h
+++ b/include/mgba/core/core.h
@@ -21,6 +21,9 @@ CXX_GUARD_START
 #ifdef USE_DEBUGGERS
 #include <mgba/debugger/debugger.h>
 #endif
+#ifdef USE_PNG
+#include <mgba-util/image/png-io.h>
+#endif
 
 enum mPlatform {
 	mPLATFORM_NONE = -1,
diff --git a/src/platform/libretro/libretro.c b/src/platform/libretro/libretro.c
index 8c08e7bb621..54a2b60a917 100644
--- a/src/platform/libretro/libretro.c
+++ b/src/platform/libretro/libretro.c
@@ -18,6 +18,7 @@
 #include <mgba/internal/gb/gb.h>
 #include <mgba/internal/gb/mbc.h>
 #include <mgba/internal/gb/overrides.h>
+#include <mgba/internal/gb/sio/printer.h>
 #endif
 #ifdef M_CORE_GBA
 #include <mgba/gba/core.h>
@@ -108,6 +109,8 @@ static bool audioLowPassEnabled = false;
 static int32_t audioLowPassRange = 0;
 static int32_t audioLowPassLeftPrev = 0;
 static int32_t audioLowPassRightPrev = 0;
+static bool printerInitDone;
+static struct GBPrinter gbPrinter;
 
 static const int keymap[] = {
 	RETRO_DEVICE_ID_JOYPAD_A,
@@ -204,6 +207,112 @@ static void _initSensors(void) {
 
 	sensorsInitDone = true;
 }
+#ifdef USE_PNG
+static void _printImage(struct GBPrinter* printer, int height, const uint8_t* data) {
+	struct mImage* image = mImageCreate(GB_VIDEO_HORIZONTAL_PIXELS, height, mCOLOR_RGB565);
+
+	uint32_t colors[4] = {
+		0xF8F8F8F8,
+		0xA8A8A8A8,
+		0x50505050,
+		0x00000000
+	};
+	for (int y = 0; y < height*2; ++y) {
+		for (int x = 0; x < GB_VIDEO_HORIZONTAL_PIXELS; x += 4) {
+			uint8_t byte = data[(x + y * GB_VIDEO_HORIZONTAL_PIXELS) / 4];
+			mImageSetPixel(image, x + 0, y, colors[(byte & 0xC0) >> 6]);
+			mImageSetPixel(image, x + 1, y, colors[(byte & 0x30) >> 4]);
+			mImageSetPixel(image, x + 2, y, colors[(byte & 0x0C) >> 2]);
+			mImageSetPixel(image, x + 3, y, colors[(byte & 0x03) >> 0]);
+		}
+	}
+	uint64_t* creationUsec = malloc(sizeof(*creationUsec));
+	if (creationUsec) {
+#ifndef _MSC_VER
+		struct timeval tv;
+		if (!gettimeofday(&tv, 0)) {
+			uint64_t usec = tv.tv_usec;
+			usec += tv.tv_sec * 1000000LL;
+			STORE_64LE(usec, 0, creationUsec);
+		}
+#else
+		struct timespec ts;
+		if (timespec_get(&ts, TIME_UTC)) {
+			uint64_t usec = ts.tv_nsec / 1000;
+			usec += ts.tv_sec * 1000000LL;
+			STORE_64LE(usec, 0, creationUsec);
+		}
+#endif
+		else {
+			free(creationUsec);
+			creationUsec = 0;
+		}
+	}
+	const char* saveDir = 0;
+	environCallback(RETRO_ENVIRONMENT_GET_SAVE_DIRECTORY, &saveDir);
+	char buf[512];
+	snprintf(buf, 512, "%sgbprinter-%llu.png", saveDir, *creationUsec);
+	free(creationUsec);
+	bool status = mImageSave(image, buf, NULL);
+	mImageDestroy(image);
+	GBPrinterDonePrinting(printer);
+}
+#endif
+#ifdef USE_DEVTERM
+static void _printDevTerm(struct GBPrinter* printer, int height, const uint8_t* data) {
+	int fd = open("/tmp/DEVTERM_PRINTER_IN", O_RDWR);
+
+	/* upscale 2x */
+	char header[14] = {
+		0x1b, 'a', '1', /*align center*/
+		0x12, '#', 9, /*set print density*/
+		0x1d, 'v', '0', 'p', 0,0,0,0 /*image header*/};
+	header[10] = (GB_VIDEO_HORIZONTAL_PIXELS * 2 / 8) % 256;
+	header[11] = (GB_VIDEO_HORIZONTAL_PIXELS * 2 / 8) / 256;
+	header[12] = (height * 2) % 256;
+	header[13] = (height * 2) / 256;
+	write(fd, header, 14);
+
+	char line_buffer [GB_VIDEO_HORIZONTAL_PIXELS / 4];
+	for (int y = 0; y < height * 2; ++y) {
+		for (int x = 0; x < GB_VIDEO_HORIZONTAL_PIXELS; x += 4) {
+			line_buffer[x/4] =
+				((((data[(x + 0 + y / 2 * GB_VIDEO_HORIZONTAL_PIXELS)/4] & 0xC0) >> 6) > 1) << 7) +
+				((((data[(x + 0 + y / 2 * GB_VIDEO_HORIZONTAL_PIXELS)/4] & 0xC0) >> 6) > 1) << 6) +
+				((((data[(x + 1 + y / 2 * GB_VIDEO_HORIZONTAL_PIXELS)/4] & 0x30) >> 4) > 1) << 5) +
+				((((data[(x + 1 + y / 2 * GB_VIDEO_HORIZONTAL_PIXELS)/4] & 0x30) >> 4) > 1) << 4) +
+				((((data[(x + 2 + y / 2 * GB_VIDEO_HORIZONTAL_PIXELS)/4] & 0x0C) >> 2) > 1) << 3) +
+				((((data[(x + 2 + y / 2 * GB_VIDEO_HORIZONTAL_PIXELS)/4] & 0x0C) >> 2) > 1) << 2) +
+				((((data[(x + 3 + y / 2 * GB_VIDEO_HORIZONTAL_PIXELS)/4] & 0x03) >> 0) > 1) << 1) +
+				((((data[(x + 3 + y / 2 * GB_VIDEO_HORIZONTAL_PIXELS)/4] & 0x03) >> 0) > 1) << 0) ;
+		}
+		write(fd, line_buffer, GB_VIDEO_HORIZONTAL_PIXELS / 4);
+	}
+	close(fd);
+	GBPrinterDonePrinting(printer);
+}
+#endif
+static void _initPrinter(void) {
+
+	if (printerInitDone) {
+		return;
+	}
+#ifdef M_CORE_GB
+	if (core->platform(core) == mPLATFORM_GB) {
+		struct GB* gb = core->board;
+		GBPrinterCreate(&gbPrinter);
+#ifdef USE_DEVTERM
+		gbPrinter.print = _printDevTerm;
+#else
+#ifdef USE_PNG
+		gbPrinter.print = _printImage;
+#endif
+#endif
+		GBSIOSetDriver(&gb->sio, &(gbPrinter.d));
+		printerInitDone = true;
+	}
+#endif
+}
 
 static void _initRumble(void) {
 	if (rumbleInitDone) {
@@ -295,6 +404,9 @@ static void _reloadSettings(void) {
 	}
 
 	_updateGbPal();
+
+	printerInitDone = false;
+	_initPrinter();
 #endif
 
 	var.key = "mgba_use_bios";
diff --git a/src/util/image.c b/src/util/image.c
index ed070f65867..05484b0fc28 100644
--- a/src/util/image.c
+++ b/src/util/image.c
@@ -208,6 +208,8 @@ bool mImageSave(const struct mImage* image, const char* path, const char* format
 
 #ifdef USE_PNG
 bool mImageSavePNG(const struct mImage* image, struct VFile* vf) {
+#ifndef COLOR_16_BIT
+#ifndef COLOR_5_6_5
 	if (image->format != mCOLOR_XBGR8 && image->format != mCOLOR_ABGR8) {
 		struct mImage* newImage;
 		if (mColorFormatHasAlpha(image->format)) {
@@ -219,12 +221,14 @@ bool mImageSavePNG(const struct mImage* image, struct VFile* vf) {
 		mImageDestroy(newImage);
 		return ret;
 	}
+#endif
+#endif
 
 	png_structp png = PNGWriteOpen(vf);
 	png_infop info = NULL;
 	bool ok = false;
 	if (png) {
-		if (image->format == mCOLOR_XBGR8) {
+		if (image->format == mCOLOR_XBGR8 || (image->format == mCOLOR_RGB565 || image->format == mCOLOR_BGR565 /*valid only with COLOR_5_6_5*/)) {
 			info = PNGWriteHeader(png, image->width, image->height);
 			if (info) {
 				ok = PNGWritePixels(png, image->width, image->height, image->stride, image->data);