diff --git a/lib/CMSIS/CM3/CoreSupport/core_cm3.c b/lib/CMSIS/CM3/CoreSupport/core_cm3.c
index 56fddc52b..0e8c3c43c 100755
--- a/lib/CMSIS/CM3/CoreSupport/core_cm3.c
+++ b/lib/CMSIS/CM3/CoreSupport/core_cm3.c
@@ -733,7 +733,7 @@ uint32_t __STREXB(uint8_t value, uint8_t *addr)
 {
    uint32_t result=0;
   
-   __ASM volatile ("strexb %0, %2, [%1]" : "=r" (result) : "r" (addr), "r" (value) );
+   __ASM volatile ("strexb %0, %2, [%1]" : "=&r" (result) : "r" (addr), "r" (value) );
    return(result);
 }
 
@@ -750,7 +750,7 @@ uint32_t __STREXH(uint16_t value, uint16_t *addr)
 {
    uint32_t result=0;
   
-   __ASM volatile ("strexh %0, %2, [%1]" : "=r" (result) : "r" (addr), "r" (value) );
+   __ASM volatile ("strexh %0, %2, [%1]" : "=&r" (result) : "r" (addr), "r" (value) );
    return(result);
 }
 
diff --git a/src/mw.c b/src/mw.c
index f8e24abc9..b82452f58 100755
--- a/src/mw.c
+++ b/src/mw.c
@@ -180,7 +180,7 @@ void annexCode(void)
             vbatRawArray[(ind++) % 8] = adcGetBattery();
             for (i = 0; i < 8; i++)
                 vbatRaw += vbatRawArray[i];
-            vbat = (((vbatRaw / 8) * 3.3f) / 4095) * 110;       // result is Vbatt in 0.1V steps
+            vbat = (((vbatRaw / 8) * 3.3f) / 4095) * 110;       // result is Vbatt in 0.1V steps. 3.3V = ADC Vref, 4095 = 12bit adc, 110 = 11:1 voltage divider (10k:1k) * 10 for 0.1V
         }
         if (rcOptions[BOXBEEPERON]) {       // unconditional beeper on via AUXn switch 
             buzzerFreq = 7;