diff --git a/media/libvpx/bug666931.patch b/media/libvpx/bug666931.patch
new file mode 100644
index 000000000000..3e580735c03b
--- /dev/null
+++ b/media/libvpx/bug666931.patch
@@ -0,0 +1,25 @@
+diff --git a/media/libvpx/build/make/ads2gas.pl b/media/libvpx/build/make/ads2gas.pl
+--- a/media/libvpx/build/make/ads2gas.pl
++++ b/media/libvpx/build/make/ads2gas.pl
+@@ -74,17 +74,20 @@ while (<STDIN>)
+ 
+     # Convert INCLUDE to .INCLUDE "file"
+     s/INCLUDE(\s*)(.*)$/.include $1\"$2\"/;
+ 
+     # Code directive (ARM vs Thumb)
+     s/CODE([0-9][0-9])/.code $1/;
+ 
+     # No AREA required
+-    s/^\s*AREA.*$/.text/;
++    # But ALIGNs in AREA must be obeyed
++    s/^\s*AREA.*ALIGN=([0-9])$/.text\n.p2align $1/;
++    # If no ALIGN, strip the AREA and align to 4 bytes
++    s/^\s*AREA.*$/.text\n.p2align 2/;
+ 
+     # DCD to .word
+     # This one is for incoming symbols
+     s/DCD\s+\|(\w*)\|/.long $1/;
+ 
+     # DCW to .short
+     s/DCW\s+\|(\w*)\|/.short $1/;
+     s/DCW(.*)/.short $1/;
diff --git a/media/libvpx/build/make/ads2gas.pl b/media/libvpx/build/make/ads2gas.pl
index 3dff048b559a..f8f03d1eb61f 100644
--- a/media/libvpx/build/make/ads2gas.pl
+++ b/media/libvpx/build/make/ads2gas.pl
@@ -79,7 +79,10 @@ while (<STDIN>)
     s/CODE([0-9][0-9])/.code $1/;
 
     # No AREA required
-    s/^\s*AREA.*$/.text/;
+    # But ALIGNs in AREA must be obeyed
+    s/^\s*AREA.*ALIGN=([0-9])$/.text\n.p2align $1/;
+    # If no ALIGN, strip the AREA and align to 4 bytes
+    s/^\s*AREA.*$/.text\n.p2align 2/;
 
     # DCD to .word
     # This one is for incoming symbols
diff --git a/media/libvpx/update.sh b/media/libvpx/update.sh
index 56748a7d7ca6..fcec84654aa9 100755
--- a/media/libvpx/update.sh
+++ b/media/libvpx/update.sh
@@ -326,3 +326,6 @@ patch -p3 < bug640935.patch
 
 # Patch to avoid text relocations on ARM
 patch -p3 < bug646815.patch
+
+# Patch to fix alignment problems with using ARM asm in Thumb mode.
+patch -p3 < bug666931.patch