Hack up an rgb_matrix config for the redox underglow. Flash with:

make redox/rev1:lenbok RGBLIGHT_ENABLE=no RGB_MATRIX_ENABLE=WS2812

keyboards/redox/keymaps/lenbok/config.h

@@ -31,5 +31,52 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #undef RGB_DI_PIN
 #define RGB_DI_PIN F4
 
+#if defined(RGBLIGHT_ENABLE)
 #undef RGBLED_NUM
-#define RGBLED_NUM 14
+#define RGBLED_NUM 14    // 14 underglow LEDs per side, but I don't use RGB_SPLIT
+
+#elif defined(RGB_MATRIX_ENABLE)
+#undef RGBLED_NUM
+#define RGBLED_NUM 28    // Total LEDs across both sides
+#define DRIVER_LED_TOTAL RGBLED_NUM
+
+//#define RGB_MATRIX_FRAMEBUFFER_EFFECTS
+#define RGB_MATRIX_MAXIMUM_BRIGHTNESS 150   // limit maximum brightness of LEDs to 150 out of 255. Higher may cause the controller to crash.
+
+#define DISABLE_RGB_MATRIX_ALPHAS_MODS
+//#define DISABLE_RGB_MATRIX_GRADIENT_UP_DOWN
+//#define DISABLE_RGB_MATRIX_BREATHING
+//#define DISABLE_RGB_MATRIX_BAND_SAT
+//#define DISABLE_RGB_MATRIX_BAND_VAL
+#define DISABLE_RGB_MATRIX_BAND_PINWHEEL_SAT
+#define DISABLE_RGB_MATRIX_BAND_PINWHEEL_VAL
+#define DISABLE_RGB_MATRIX_BAND_SPIRAL_SAT
+#define DISABLE_RGB_MATRIX_BAND_SPIRAL_VAL
+#define DISABLE_RGB_MATRIX_CYCLE_ALL
+//#define DISABLE_RGB_MATRIX_CYCLE_LEFT_RIGHT
+#define DISABLE_RGB_MATRIX_CYCLE_UP_DOWN
+//#define DISABLE_RGB_MATRIX_RAINBOW_MOVING_CHEVRON
+#define DISABLE_RGB_MATRIX_CYCLE_OUT_IN
+#define DISABLE_RGB_MATRIX_CYCLE_OUT_IN_DUAL
+#define DISABLE_RGB_MATRIX_CYCLE_PINWHEEL
+#define DISABLE_RGB_MATRIX_CYCLE_SPIRAL
+#define DISABLE_RGB_MATRIX_DUAL_BEACON
+#define DISABLE_RGB_MATRIX_RAINBOW_BEACON
+#define DISABLE_RGB_MATRIX_RAINBOW_PINWHEELS
+#define DISABLE_RGB_MATRIX_RAINDROPS
+#define DISABLE_RGB_MATRIX_JELLYBEAN_RAINDROPS
+#define DISABLE_RGB_MATRIX_TYPING_HEATMAP
+#define DISABLE_RGB_MATRIX_DIGITAL_RAIN
+#define DISABLE_RGB_MATRIX_SOLID_REACTIVE
+#define DISABLE_RGB_MATRIX_SOLID_REACTIVE_SIMPLE
+#define DISABLE_RGB_MATRIX_SOLID_REACTIVE_WIDE
+#define DISABLE_RGB_MATRIX_SOLID_REACTIVE_MULTIWIDE
+#define DISABLE_RGB_MATRIX_SOLID_REACTIVE_CROSS
+#define DISABLE_RGB_MATRIX_SOLID_REACTIVE_MULTICROSS
+#define DISABLE_RGB_MATRIX_SOLID_REACTIVE_NEXUS
+#define DISABLE_RGB_MATRIX_SOLID_REACTIVE_MULTINEXUS
+#define DISABLE_RGB_MATRIX_SPLASH
+#define DISABLE_RGB_MATRIX_MULTISPLASH
+#define DISABLE_RGB_MATRIX_SOLID_SPLASH
+#define DISABLE_RGB_MATRIX_SOLID_MULTISPLASH
+#endif

keyboards/redox/keymaps/lenbok/keymap.c

@@ -64,3 +64,28 @@ const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
   )
 };
 
+#ifdef RGB_MATRIX_ENABLE
+// 14 underglow LEDs per side
+led_config_t g_led_config = { {
+    {  NO_LED, NO_LED, NO_LED, NO_LED, NO_LED, NO_LED, NO_LED },
+    {  NO_LED, NO_LED, NO_LED, NO_LED, NO_LED, NO_LED, NO_LED },
+    {  NO_LED, NO_LED, NO_LED, NO_LED, NO_LED, NO_LED, NO_LED },
+    {  NO_LED, NO_LED, NO_LED, NO_LED, NO_LED, NO_LED, NO_LED },
+    {  NO_LED, NO_LED, NO_LED, NO_LED, NO_LED, NO_LED, NO_LED },
+    {  NO_LED, NO_LED, NO_LED, NO_LED, NO_LED, NO_LED, NO_LED },
+    {  NO_LED, NO_LED, NO_LED, NO_LED, NO_LED, NO_LED, NO_LED },
+    {  NO_LED, NO_LED, NO_LED, NO_LED, NO_LED, NO_LED, NO_LED },
+    {  NO_LED, NO_LED, NO_LED, NO_LED, NO_LED, NO_LED, NO_LED },
+    {  NO_LED, NO_LED, NO_LED, NO_LED, NO_LED, NO_LED, NO_LED }
+}, {
+    { 104,  16 }, {  96,  16 }, {  88,  16 }, {  80,  16 }, {  72,  16 }, {  64,  16 }, {  56,  16 },
+    {  48,  16 }, {  40,  16 }, {  32,  16 }, {  24,  16 }, {  16,  16 }, {   8,  16 }, {   0,  16 },
+    { 120,  16 }, { 128,  16 }, { 136,  16 }, { 144,  16 }, { 152,  16 }, { 160,  16 }, { 168,  16 },
+    { 176,  16 }, { 184,  16 }, { 192,  16 }, { 200,  16 }, { 208,  16 }, { 216,  16 }, { 224,  16 }
+}, {
+    2, 2, 2, 2, 2, 2, 2,
+    2, 2, 2, 2, 2, 2, 2,
+    2, 2, 2, 2, 2, 2, 2,
+    2, 2, 2, 2, 2, 2, 2
+} };
+#endif