ergodox.c.patch

-        // read from teensy
-        return
-            (PINF&(1<<0) ? 0 : (1<<0)) |
-            (PINF&(1<<1) ? 0 : (1<<1)) |
-            (PINF&(1<<4) ? 0 : (1<<2)) |
-            (PINF&(1<<5) ? 0 : (1<<3)) |
-            (PINF&(1<<6) ? 0 : (1<<4)) |
-            (PINF&(1<<7) ? 0 : (1<<5)) ;
+        /* read from teensy
+        * bitmask is 0b11110011, but we want those all
+        * in the lower six bits.
+        * we'll return 1s for the top two, but that's harmless.
+        */
+
+        return ~((PINF & 0x03) | ((PINF & 0xF0) >> 2));