diff --git src/common/imageio_jpeg.c src/common/imageio_jpeg.c
index 40f82ff..1b1b0be 100644
--- src/common/imageio_jpeg.c
+++ src/common/imageio_jpeg.c
@@ -99,7 +99,7 @@ int dt_imageio_jpeg_decompress_header(const void *in, size_t length, dt_imageio_
 
   jpg->dinfo.src = &(jpg->src);
   // jpg->dinfo.buffered_image = TRUE;
-  jpeg_read_header(&(jpg->dinfo), TRUE);
+  jpeg_read_header(&(jpg->dinfo), (boolean)TRUE);
   jpg->width = jpg->dinfo.image_width;
   jpg->height = jpg->dinfo.image_height;
   return 0;
@@ -483,7 +483,7 @@ int dt_imageio_jpeg_read_header(const char *filename, dt_imageio_jpeg_t *jpg)
   jpeg_stdio_src(&(jpg->dinfo), jpg->f);
   setup_read_icc_profile(&(jpg->dinfo));
   // jpg->dinfo.buffered_image = TRUE;
-  jpeg_read_header(&(jpg->dinfo), TRUE);
+  jpeg_read_header(&(jpg->dinfo), (boolean)TRUE);
   jpg->width = jpg->dinfo.image_width;
   jpg->height = jpg->dinfo.image_height;
   return 0;
diff --git src/external/rawspeed/RawSpeed/DngDecoderSlices.cpp src/external/rawspeed/RawSpeed/DngDecoderSlices.cpp
index bdafb7e..72a80c5 100644
--- src/external/rawspeed/RawSpeed/DngDecoderSlices.cpp
+++ src/external/rawspeed/RawSpeed/DngDecoderSlices.cpp
@@ -177,7 +177,7 @@ void DngDecoderSlices::decodeSlice(DngDecoderThread* t) {
         CHECKSIZE(e.byteOffset+e.byteCount);
         JPEG_MEMSRC(&dinfo, (unsigned char*)mFile->getData(e.byteOffset), e.byteCount);
 
-        if (JPEG_HEADER_OK != jpeg_read_header(&dinfo, TRUE))
+        if (JPEG_HEADER_OK != jpeg_read_header(&dinfo, (boolean)TRUE))
           ThrowRDE("DngDecoderSlices: Unable to read JPEG header");
 
         jpeg_start_decompress(&dinfo);
diff --git src/imageio/format/jpeg.c src/imageio/format/jpeg.c
index 510318b..383708c 100644
--- src/imageio/format/jpeg.c
+++ src/imageio/format/jpeg.c
@@ -416,7 +416,7 @@ int read_header(const char *filename, dt_imageio_jpeg_t *jpg)
   jpeg_create_decompress(&(jpg->dinfo));
   jpeg_stdio_src(&(jpg->dinfo), jpg->f);
   // jpg->dinfo.buffered_image = TRUE;
-  jpeg_read_header(&(jpg->dinfo), TRUE);
+  jpeg_read_header(&(jpg->dinfo), (boolean)TRUE);
   jpg->width = jpg->dinfo.image_width;
   jpg->height = jpg->dinfo.image_height;
   return 0;