add '#define SOFT_SERIAL_PIN D0' to keyboards/redox/rev1/config.h

keyboards/redox/rev1/config.h

@@ -49,6 +49,9 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 /* Set 0 if debouncing isn't needed */
 #define DEBOUNCING_DELAY 5
 
+/* serial.c configuration for split keyboard */
+#define SOFT_SERIAL_PIN D0
+
 /* Mechanical locking support. Use KC_LCAP, KC_LNUM or KC_LSCR instead in keymap */
 #define LOCKING_SUPPORT_ENABLE
 /* Locking resynchronize hack */

quantum/split_common/split-keyboards-list.txt

@@ -13,7 +13,7 @@ ok keyboards/miniaxe/rules.mk:SPLIT_KEYBOARD = yes        # Use shared split_com
 ok keyboards/nyquist/rules.mk:SPLIT_KEYBOARD = yes
 ok keyboards/quefrency/rules.mk:SPLIT_KEYBOARD = yes
 ok keyboards/qwertyydox/rules.mk:SPLIT_KEYBOARD = yes
-keyboards/redox/rules.mk:SPLIT_KEYBOARD = yes
+ok keyboards/redox/rules.mk:SPLIT_KEYBOARD = yes
 keyboards/rorschach/rules.mk:SPLIT_KEYBOARD = yes
 
 $ find keyboards/6lit keyboards/divergetm2 keyboards/ergotravel keyboards/foobar keyboards/handwired/dactyl_manuform keyboards/handwired/qc60 keyboards/handwired/xealous keyboards/iris keyboards/lets_split_eh keyboards/levinson keyboards/miniaxe keyboards/nyquist keyboards/quefrency keyboards/qwertyydox keyboards/redox keyboards/rorschach -name config.h | xargs grep USE_I2C | grep -v '://'