--- backend/channel-usb.c
+++ backend/channel-usb.c
@@ -91,6 +91,7 @@ static ssize_t channel_usb_send (channel *, const void *,
 static ssize_t channel_usb_recv (channel *, void *,
                                  size_t, SANE_Status *);
 
+static size_t channel_usb_max_request_size (const channel *);
 
 channel *
 channel_usb_ctor (channel *self, const char *dev_name, SANE_Status *status)
@@ -119,7 +120,7 @@ channel_usb_ctor (channel *self, const char *dev_name, SANE_Status *status)
   self->send = channel_usb_send;
   self->recv = channel_usb_recv;
 
-  self->max_size = 128 * 1024;
+  self->max_request_size = channel_usb_max_request_size;
 
   return self;
 }
@@ -265,9 +266,6 @@ channel_interpreter_ctor (channel *self, const char *dev_name,
           self->dtor = channel_interpreter_dtor;
         }
     }
-
-  self->max_size = 32 * 1024;
-
   return self;
 }
 
@@ -283,3 +281,10 @@ channel_interpreter_dtor (channel *self)
   self->dtor = channel_dtor;
   return self->dtor (self);
 }
+
+static size_t
+channel_usb_max_request_size (const channel *self)
+{
+  return (self->interpreter ? 32 : 128) * 1024;
+}
+
--- backend/dip-obj.c
+++ backend/dip-obj.c
@@ -555,44 +555,70 @@ dip_change_GRB_to_RGB (const void *self, const buffer *buf)
   return;
 }
 
-/*! \todo Add support for 16 bit color values (#816).
- */
 void
 dip_apply_color_profile (const void *self, const buffer *buf,
                          const double profile[9])
 {
   SANE_Int i;
-  SANE_Byte *r_buf, *g_buf, *b_buf;
   double red, grn, blu;
 
-  SANE_Byte *data;
   SANE_Int size;
 
   require (dip == self && buf && profile);
-  require (8 == buf->ctx.depth);
+  require (buf->ctx.depth == 8 || buf->ctx.depth == 16);
 
   if (SANE_FRAME_RGB != buf->ctx.format)
     return;
 
-  data = buf->ptr;
-  size = buf->end - buf->ptr;
+  if (buf->ctx.depth == 8)
+  {
+    SANE_Byte *r_buf, *g_buf, *b_buf;
+    SANE_Byte *data;
+
+    data = buf->ptr;
+    size = buf->end - buf->ptr;
 
-  for (i = 0; i < size / 3; i++)
+    for (i = 0; i < size / 3; i++)
+    {
+      r_buf = data;
+      g_buf = data + 1;
+      b_buf = data + 2;
+
+      red =
+	profile[0] * (*r_buf) + profile[1] * (*g_buf) + profile[2] * (*b_buf);
+      grn =
+	profile[3] * (*r_buf) + profile[4] * (*g_buf) + profile[5] * (*b_buf);
+      blu =
+	profile[6] * (*r_buf) + profile[7] * (*g_buf) + profile[8] * (*b_buf);
+
+      *data++ = clamp (red, 0, 255);
+      *data++ = clamp (grn, 0, 255);
+      *data++ = clamp (blu, 0, 255);
+    }
+  }
+  else if (buf->ctx.depth == 16)
   {
-    r_buf = data;
-    g_buf = data + 1;
-    b_buf = data + 2;
-
-    red =
-      profile[0] * (*r_buf) + profile[1] * (*g_buf) + profile[2] * (*b_buf);
-    grn =
-      profile[3] * (*r_buf) + profile[4] * (*g_buf) + profile[5] * (*b_buf);
-    blu =
-      profile[6] * (*r_buf) + profile[7] * (*g_buf) + profile[8] * (*b_buf);
-
-    *data++ = clamp (red, 0, 255);
-    *data++ = clamp (grn, 0, 255);
-    *data++ = clamp (blu, 0, 255);
+    uint16_t *r_buf, *g_buf, *b_buf;
+    uint16_t *data;
+
+    data = (uint16_t *)buf->ptr;
+    while(data < buf->end)
+    {
+      r_buf = data;
+      g_buf = data + 1;
+      b_buf = data + 2;
+
+      red =
+	profile[0] * (*r_buf) + profile[1] * (*g_buf) + profile[2] * (*b_buf);
+      grn =
+	profile[3] * (*r_buf) + profile[4] * (*g_buf) + profile[5] * (*b_buf);
+      blu =
+	profile[6] * (*r_buf) + profile[7] * (*g_buf) + profile[8] * (*b_buf);
+
+      *data++ = clamp (red, 0, 65535);
+      *data++ = clamp (grn, 0, 65535);
+      *data++ = clamp (blu, 0, 65535);
+    }
   }
 }