Turn on register 0x8B5 LSB for improved RX, turn off boosted gain

src/helpers/radiolib/CustomSX1262.h

@@ -76,6 +76,14 @@ class CustomSX1262 : public SX1262 {
       setRfSwitchPins(SX126X_RXEN, SX126X_TXEN);
   #endif 
 
+  // for improved RX with Heltec v4
+  #ifdef SX126X_REGISTER_PATCH
+    uint8_t r_data = 0;
+    readRegister(0x8B5, &r_data, 1);
+    r_data |= 0x01;
+    writeRegister(0x8B5, &r_data, 1);
+  #endif
+
       return true;  // success
     }
 

variants/heltec_v4/platformio.ini

@@ -17,9 +17,9 @@ build_flags =
   -D P_LORA_SCLK=9
   -D P_LORA_MISO=11
   -D P_LORA_MOSI=10
-  -D P_LORA_PA_POWER=7   ;power en
-  -D P_LORA_PA_EN=2
-  -D P_LORA_PA_TX_EN=46  ;enable tx
+  -D P_LORA_PA_POWER=7   ; VFEM_Ctrl - Power on GC1109
+  -D P_LORA_PA_EN=2      ; PA CSD - Enable GC1109
+  -D P_LORA_PA_TX_EN=46  ; PA CPS - GC1109 TX PA full(High) / bypass(Low)
   -D PIN_BOARD_SDA=17
   -D PIN_BOARD_SCL=18
   -D PIN_USER_BTN=0
@@ -27,10 +27,11 @@ build_flags =
   -D PIN_VEXT_EN_ACTIVE=HIGH
   -D LORA_TX_POWER=10 ;If it is configured as 10 here, the final output will be 22 dbm.
   -D MAX_LORA_TX_POWER=22 ; Max SX1262 output
-  -D SX126X_DIO2_AS_RF_SWITCH=true
+  -D SX126X_REGISTER_PATCH=1       ; Patch register 0x8B5 for improved RX
+  -D SX126X_DIO2_AS_RF_SWITCH=true ; GC1109 CTX is controlled by SX1262 DIO2
   -D SX126X_DIO3_TCXO_VOLTAGE=1.8
   -D SX126X_CURRENT_LIMIT=140
-  -D SX126X_RX_BOOSTED_GAIN=1
+;  -D SX126X_RX_BOOSTED_GAIN=1      ; Turned off for improved RX
   -D PIN_GPS_RX=38
   -D PIN_GPS_TX=39
   -D PIN_GPS_RESET=42