diff --git a/main/configuration.h b/main/configuration.h
index 7e157eb..022db6b 100644
--- a/main/configuration.h
+++ b/main/configuration.h
@@ -82,16 +82,21 @@ void ttn_register(void (*callback)(uint8_t message));
 // General
 // -----------------------------------------------------------------------------
 
-#define BUTTON_PIN      39
+#define I2C_SDA         21
+#define I2C_SCL         22
 #define LED_PIN         14
 
+#if defined(T_BEAM_V07)
+#define BUTTON_PIN      39
+#elif defined(T_BEAM_V10)
+#define BUTTON_PIN      38
+#endif
+
 // -----------------------------------------------------------------------------
 // OLED
 // -----------------------------------------------------------------------------
 
 #define OLED_ADDRESS    0x3C
-#define OLED_SDA        21
-#define OLED_SCL        22
 
 // -----------------------------------------------------------------------------
 // GPS
@@ -123,11 +128,10 @@ void ttn_register(void (*callback)(uint8_t message));
 #define DIO2_GPIO       32
 
 // -----------------------------------------------------------------------------
-// Rev1-specific options
+// AXP192 (Rev1-specific options)
 // -----------------------------------------------------------------------------
 
-#ifdef T_BEAM_V10
-#define GPS_POWER_CTRL_CH  3
-#define LORA_POWER_CTRL_CH 2
-#define PMU_IRQ            35
-#endif
+#define AXP192_SLAVE_ADDRESS  0x34
+#define GPS_POWER_CTRL_CH     3
+#define LORA_POWER_CTRL_CH    2
+#define PMU_IRQ               35
diff --git a/main/main.ino b/main/main.ino
index 6ff88ff..a7ef624 100644
--- a/main/main.ino
+++ b/main/main.ino
@@ -23,10 +23,11 @@
 
 #include "configuration.h"
 #include "rom/rtc.h"
+#include <TinyGPS++.h>
+#include <Wire.h>
 
 #ifdef T_BEAM_V10
 #include "axp20x.h"
-#define AXP192_SLAVE_ADDRESS    0x34
 AXP20X_Class axp;
 bool axp192_found = false;
 bool pmu_irq = false;
@@ -35,10 +36,6 @@ String baChStatus = "No charging";
 
 // Message counter, stored in RTC memory, survives deep sleep
 RTC_DATA_ATTR uint32_t count = 0;
-// -----------------------------------------------------------------------------
-// Submodules
-// -----------------------------------------------------------------------------
-#include <TinyGPS++.h>
 
 #if defined(PAYLOAD_USE_FULL)
   // includes number of satellites and accuracy
@@ -144,7 +141,8 @@ void setup() {
   #endif
 
   #ifdef T_BEAM_V10
-  axp192_found = 1;
+  Wire.begin(I2C_SDA, I2C_SCL);
+  axp192_found = true;
   if (axp192_found) {
       if (!axp.begin(Wire, AXP192_SLAVE_ADDRESS)) {
           Serial.println("AXP192 Begin PASS");
diff --git a/main/screen.ino b/main/screen.ino
index e000c4b..3cecc15 100644
--- a/main/screen.ino
+++ b/main/screen.ino
@@ -93,7 +93,7 @@ void screen_update() {
 
 void screen_setup() {
     // Display instance
-    display = new SSD1306Wire(OLED_ADDRESS, OLED_SDA, OLED_SCL);
+    display = new SSD1306Wire(OLED_ADDRESS, I2C_SDA, I2C_SCL);
     display->init();
     display->flipScreenVertically();
     display->setFont(Custom_ArialMT_Plain_10);