diff --git a/Tests/images/bc1.dds b/Tests/images/bc1.dds
new file mode 100755
index 000000000..faec63a00
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diff --git a/Tests/images/bc1_typeless.dds b/Tests/images/bc1_typeless.dds
new file mode 100755
index 000000000..47a85e2d0
Binary files /dev/null and b/Tests/images/bc1_typeless.dds differ
diff --git a/Tests/images/rgb8.dds b/Tests/images/rgb8.dds
new file mode 100644
index 000000000..8193e8e5a
Binary files /dev/null and b/Tests/images/rgb8.dds differ
diff --git a/Tests/images/unsupported_bitcount_luminance.dds b/Tests/images/unsupported_bitcount_luminance.dds
new file mode 100644
index 000000000..f9bb82254
Binary files /dev/null and b/Tests/images/unsupported_bitcount_luminance.dds differ
diff --git a/Tests/images/unsupported_bitcount_rgb.dds b/Tests/images/unsupported_bitcount_rgb.dds
new file mode 100644
index 000000000..77d527507
Binary files /dev/null and b/Tests/images/unsupported_bitcount_rgb.dds differ
diff --git a/Tests/test_file_dds.py b/Tests/test_file_dds.py
index 72bb2df7b..bed143656 100644
--- a/Tests/test_file_dds.py
+++ b/Tests/test_file_dds.py
@@ -15,6 +15,8 @@ TEST_FILE_ATI2 = "Tests/images/ati2.dds"
 TEST_FILE_DX10_BC5_TYPELESS = "Tests/images/bc5_typeless.dds"
 TEST_FILE_DX10_BC5_UNORM = "Tests/images/bc5_unorm.dds"
 TEST_FILE_DX10_BC5_SNORM = "Tests/images/bc5_snorm.dds"
+TEST_FILE_DX10_BC1 = "Tests/images/bc1.dds"
+TEST_FILE_DX10_BC1_TYPELESS = "Tests/images/bc1_typeless.dds"
 TEST_FILE_BC5S = "Tests/images/bc5s.dds"
 TEST_FILE_BC5U = "Tests/images/bc5u.dds"
 TEST_FILE_BC6H = "Tests/images/bc6h.dds"
@@ -29,11 +31,20 @@ TEST_FILE_UNCOMPRESSED_RGB = "Tests/images/hopper.dds"
 TEST_FILE_UNCOMPRESSED_RGB_WITH_ALPHA = "Tests/images/uncompressed_rgb.dds"
 
 
-def test_sanity_dxt1():
+@pytest.mark.parametrize(
+    "image_path",
+    (
+        TEST_FILE_DXT1,
+        # hexeditted to use DX10 FourCC
+        TEST_FILE_DX10_BC1,
+        TEST_FILE_DX10_BC1_TYPELESS,
+    ),
+)
+def test_sanity_bc1(image_path):
     """Check DXT1 images can be opened"""
     with Image.open(TEST_FILE_DXT1.replace(".dds", ".png")) as target:
         target = target.convert("RGBA")
-    with Image.open(TEST_FILE_DXT1) as im:
+    with Image.open(image_path) as im:
         im.load()
 
         assert im.format == "DDS"
@@ -306,8 +317,19 @@ def test_palette():
 @pytest.mark.parametrize(
     "test_file",
     (
-        "Tests/images/unknown_fourcc.dds",
-        "Tests/images/unimplemented_fourcc.dds",
+        "Tests/images/unsupported_bitcount_rgb.dds",
+        "Tests/images/unsupported_bitcount_luminance.dds",
+    ),
+)
+def test_unsupported_bitcount(test_file):
+    with pytest.raises(OSError):
+        with Image.open(test_file):
+            pass
+
+
+@pytest.mark.parametrize(
+    "test_file",
+    (
         "Tests/images/unimplemented_dxgi_format.dds",
         "Tests/images/unimplemented_pfflags.dds",
     ),
@@ -340,6 +362,12 @@ def test_open(mode, test_file):
         assert_image_equal_tofile(im, test_file.replace(".dds", ".png"))
 
 
+def test_open_rgb8():
+    with Image.open("Tests/images/rgb8.dds") as im:
+        assert im.mode == "L"
+        assert_image_equal_tofile(im, "Tests/images/mode-l.png")
+
+
 @pytest.mark.parametrize(
     ("mode", "test_file"),
     [
diff --git a/src/PIL/DdsImagePlugin.py b/src/PIL/DdsImagePlugin.py
index bf3807c84..467030114 100644
--- a/src/PIL/DdsImagePlugin.py
+++ b/src/PIL/DdsImagePlugin.py
@@ -346,34 +346,27 @@ class DdsImageFile(ImageFile.ImageFile):
         # pixel format
         pfsize, pfflags, fourcc, bitcount = struct.unpack("<4I", header.read(16))
         masks = struct.unpack("<4I", header.read(16))
-        if flags & DDSD.CAPS:
-            header.seek(20, io.SEEK_CUR)
         n = 0
         rawmode = None
         if pfflags & DDPF.RGB:
             # Texture contains uncompressed RGB data
             masks = {mask: ["R", "G", "B", "A"][i] for i, mask in enumerate(masks)}
-            if bitcount == 24:
+            if bitcount == 8:
+                self._mode = "L"
+            elif bitcount == 24:
                 self._mode = "RGB"
-                rawmode = masks[0x00FF0000] + masks[0x0000FF00] + masks[0x000000FF]
+                rawmode = masks[0x000000FF] + masks[0x0000FF00] + masks[0x00FF0000]
             elif bitcount == 32 and pfflags & DDPF.ALPHAPIXELS:
                 self._mode = "RGBA"
                 rawmode = (
-                    masks[0xFF000000]
-                    + masks[0x00FF0000]
+                    masks[0x000000FF]
                     + masks[0x0000FF00]
-                    + masks[0x000000FF]
+                    + masks[0x00FF0000]
+                    + masks[0xFF000000]
                 )
             else:
                 msg = f"Unsupported bitcount {bitcount} for {pfflags}"
                 raise OSError(msg)
-            rawmode = rawmode[::-1]
-        elif pfflags & DDPF.ALPHA:
-            if bitcount == 8:
-                self._mode = "L"
-            else:
-                msg = f"Unsupported bitcount {bitcount} for {pfflags}"
-                raise OSError(msg)
         elif pfflags & DDPF.LUMINANCE:
             if bitcount == 8:
                 self._mode = "L"
@@ -418,7 +411,6 @@ class DdsImageFile(ImageFile.ImageFile):
                 self.fp.read(16)
                 if dxgi_format in (
                     DXGI_FORMAT.BC1_UNORM,
-                    DXGI_FORMAT.BC1_UNORM_SRGB,
                     DXGI_FORMAT.BC1_TYPELESS,
                 ):
                     self._mode = "RGBA"