diff --git a/src/modules/SX128x/SX128x.cpp b/src/modules/SX128x/SX128x.cpp
index 288ec928..3c18d68d 100644
--- a/src/modules/SX128x/SX128x.cpp
+++ b/src/modules/SX128x/SX128x.cpp
@@ -772,8 +772,7 @@ int16_t SX128x::setModem(ModemType_t modem) {
 int16_t SX128x::getModem(ModemType_t* modem) {
   RADIOLIB_ASSERT_PTR(modem);
 
-  uint8_t packetType = getPacketType();
-  switch(packetType) {
+  switch(getPacketType()) {
     case(RADIOLIB_SX128X_PACKET_TYPE_LORA):
       *modem = ModemType_t::RADIOLIB_MODEM_LORA;
       return(RADIOLIB_ERR_NONE);
@@ -827,7 +826,7 @@ int16_t SX128x::setPreambleLength(uint32_t preambleLength) {
 
     // update packet parameters
     this->preambleLengthGFSK = ((preambleLength / 4) - 1) << 4;
-    return(setPacketParamsGFSK(this->preambleLengthGFSK, this->syncWordLen, this->syncWordMatch, this->crcGFSK, this->whitening));
+    return(setPacketParamsGFSK(this->preambleLengthGFSK, this->syncWordLen, this->syncWordMatch, this->crcGFSK, this->whitening, this->packetType));
   }
 
   return(RADIOLIB_ERR_WRONG_MODEM);
@@ -1014,7 +1013,7 @@ int16_t SX128x::setSyncWord(const uint8_t* syncWord, uint8_t len) {
     /// \todo add support for multiple sync words
     this->syncWordMatch = RADIOLIB_SX128X_GFSK_FLRC_SYNC_WORD_1;
   }
-  return(setPacketParamsGFSK(this->preambleLengthGFSK, this->syncWordLen, this->syncWordMatch, this->crcGFSK, this->whitening));
+  return(setPacketParamsGFSK(this->preambleLengthGFSK, this->syncWordLen, this->syncWordMatch, this->crcGFSK, this->whitening, this->packetType));
 }
 
 int16_t SX128x::setSyncWord(uint8_t syncWord, uint8_t controlBits) {
@@ -1045,7 +1044,7 @@ int16_t SX128x::setCRC(uint8_t len, uint32_t initial, uint16_t polynomial) {
       }
     }
     this->crcGFSK = len << 4;
-    state = setPacketParamsGFSK(this->preambleLengthGFSK, this->syncWordLen, this->syncWordMatch, this->crcGFSK, this->whitening);
+    state = setPacketParamsGFSK(this->preambleLengthGFSK, this->syncWordLen, this->syncWordMatch, this->crcGFSK, this->whitening, this->packetType);
     RADIOLIB_ASSERT(state);
 
     // set initial CRC value
@@ -1107,7 +1106,7 @@ int16_t SX128x::setWhitening(bool enabled) {
   }
 
   if(modem == RADIOLIB_SX128X_PACKET_TYPE_GFSK) {
-    return(setPacketParamsGFSK(this->preambleLengthGFSK, this->syncWordLen, this->syncWordMatch, this->crcGFSK, this->whitening));
+    return(setPacketParamsGFSK(this->preambleLengthGFSK, this->syncWordLen, this->syncWordMatch, this->crcGFSK, this->whitening, this->packetType));
   }
   return(setPacketParamsBLE(this->connectionState, this->crcBLE, this->bleTestPayload, this->whitening));
 }
@@ -1284,6 +1283,14 @@ size_t SX128x::getPacketLength(bool update, uint8_t* offset) {
   return((size_t)rxBufStatus[0]);
 }
 
+int16_t SX128x::fixedPacketLengthMode(uint8_t len) {
+  return(setPacketMode(RADIOLIB_SX128X_GFSK_FLRC_PACKET_FIXED, len));
+}
+
+int16_t SX128x::variablePacketLengthMode(uint8_t maxLen) {
+  return(setPacketMode(RADIOLIB_SX128X_GFSK_FLRC_PACKET_VARIABLE, maxLen));
+}
+
 RadioLibTime_t SX128x::getTimeOnAir(size_t len) {
   // check active modem
   uint8_t modem = getPacketType();
@@ -1439,7 +1446,7 @@ int16_t SX128x::stageMode(RadioModeType_t mode, RadioModeConfig_t* cfg) {
       if(modem == RADIOLIB_SX128X_PACKET_TYPE_LORA) {
         state = setPacketParamsLoRa(this->preambleLengthLoRa, this->headerType, cfg->transmit.len, this->crcLoRa, this->invertIQEnabled);
       } else if((modem == RADIOLIB_SX128X_PACKET_TYPE_GFSK) || (modem == RADIOLIB_SX128X_PACKET_TYPE_FLRC)) {
-        state = setPacketParamsGFSK(this->preambleLengthGFSK, this->syncWordLen, this->syncWordMatch, this->crcGFSK, this->whitening, cfg->transmit.len);
+        state = setPacketParamsGFSK(this->preambleLengthGFSK, this->syncWordLen, this->syncWordMatch, this->crcGFSK, this->whitening, this->packetType, cfg->transmit.len);
       } else if(modem == RADIOLIB_SX128X_PACKET_TYPE_BLE) {
         state = setPacketParamsBLE(this->connectionState, this->crcBLE, this->bleTestPayload, this->whitening);
       } else {
@@ -1603,7 +1610,7 @@ int16_t SX128x::setModulationParams(uint8_t modParam1, uint8_t modParam2, uint8_
   return(this->mod->SPIwriteStream(RADIOLIB_SX128X_CMD_SET_MODULATION_PARAMS, data, 3));
 }
 
-int16_t SX128x::setPacketParamsGFSK(uint8_t preambleLen, uint8_t syncLen, uint8_t syncMatch, uint8_t crcLen, uint8_t whiten, uint8_t payLen, uint8_t hdrType) {
+int16_t SX128x::setPacketParamsGFSK(uint8_t preambleLen, uint8_t syncLen, uint8_t syncMatch, uint8_t crcLen, uint8_t whiten, uint8_t hdrType, uint8_t payLen) {
   const uint8_t data[] = { preambleLen, syncLen, syncMatch, hdrType, payLen, crcLen, whiten };
   return(this->mod->SPIwriteStream(RADIOLIB_SX128X_CMD_SET_PACKET_PARAMS, data, 7));
 }
@@ -1647,6 +1654,21 @@ int16_t SX128x::setPacketType(uint8_t type) {
   return(this->mod->SPIwriteStream(RADIOLIB_SX128X_CMD_SET_PACKET_TYPE, data, 1));
 }
 
+int16_t SX128x::setPacketMode(uint8_t mode, uint8_t len) {
+  // check active modem
+  if(getPacketType() != RADIOLIB_SX128X_PACKET_TYPE_GFSK) {
+    return(RADIOLIB_ERR_WRONG_MODEM);
+  }
+
+  // set requested packet mode
+  int16_t state = setPacketParamsGFSK(this->preambleLengthGFSK, this->syncWordLen, this->syncWordMatch, this->crcGFSK, this->whitening, mode, len);
+  RADIOLIB_ASSERT(state);
+
+  // update cached value
+  this->packetType = mode;
+  return(state);
+}
+
 int16_t SX128x::setHeaderType(uint8_t hdrType, size_t len) {
   // check active modem
   uint8_t modem = getPacketType();
diff --git a/src/modules/SX128x/SX128x.h b/src/modules/SX128x/SX128x.h
index 0211ed26..0fe91a4b 100644
--- a/src/modules/SX128x/SX128x.h
+++ b/src/modules/SX128x/SX128x.h
@@ -795,6 +795,20 @@ class SX128x: public PhysicalLayer {
     */
     size_t getPacketLength(bool update, uint8_t* offset);
 
+    /*!
+      \brief Set modem in fixed packet length mode. Available in GFSK mode only.
+      \param len Packet length.
+      \returns \ref status_codes
+    */
+    int16_t fixedPacketLengthMode(uint8_t len = RADIOLIB_SX128X_MAX_PACKET_LENGTH);
+
+    /*!
+      \brief Set modem in variable packet length mode. Available in GFSK mode only.
+      \param maxLen Maximum packet length.
+      \returns \ref status_codes
+    */
+    int16_t variablePacketLengthMode(uint8_t maxLen = RADIOLIB_SX128X_MAX_PACKET_LENGTH);
+
     /*!
       \brief Get expected time-on-air for a given size of payload.
       \param len Payload length in bytes.
@@ -885,7 +899,7 @@ class SX128x: public PhysicalLayer {
     int16_t setTxParams(uint8_t pwr, uint8_t rampTime = RADIOLIB_SX128X_PA_RAMP_10_US);
     int16_t setBufferBaseAddress(uint8_t txBaseAddress = 0x00, uint8_t rxBaseAddress = 0x00);
     int16_t setModulationParams(uint8_t modParam1, uint8_t modParam2, uint8_t modParam3);
-    int16_t setPacketParamsGFSK(uint8_t preambleLen, uint8_t syncLen, uint8_t syncMatch, uint8_t crcLen, uint8_t whiten, uint8_t payLen = 0xFF, uint8_t hdrType = RADIOLIB_SX128X_GFSK_FLRC_PACKET_VARIABLE);
+    int16_t setPacketParamsGFSK(uint8_t preambleLen, uint8_t syncLen, uint8_t syncMatch, uint8_t crcLen, uint8_t whiten, uint8_t hdrType, uint8_t payLen = 0xFF);
     int16_t setPacketParamsBLE(uint8_t connState, uint8_t crcLen, uint8_t bleTest, uint8_t whiten);
     int16_t setPacketParamsLoRa(uint8_t preambleLen, uint8_t hdrType, uint8_t payLen, uint8_t crc, uint8_t invIQ = RADIOLIB_SX128X_LORA_IQ_STANDARD);
     int16_t setDioIrqParams(uint16_t irqMask, uint16_t dio1Mask, uint16_t dio2Mask = RADIOLIB_SX128X_IRQ_NONE, uint16_t dio3Mask = RADIOLIB_SX128X_IRQ_NONE);
@@ -913,6 +927,7 @@ class SX128x: public PhysicalLayer {
     uint16_t bitRateKbps = 0;
     uint8_t bitRate = 0, modIndex = 0, shaping = 0;
     uint8_t preambleLengthGFSK = 0, syncWordLen = 0, syncWordMatch = 0, crcGFSK = 0, whitening = 0;
+    uint8_t packetType = RADIOLIB_SX128X_GFSK_FLRC_PACKET_VARIABLE;
 
     // cached FLRC parameters
     uint8_t codingRateFLRC = 0;
@@ -921,6 +936,7 @@ class SX128x: public PhysicalLayer {
     uint8_t connectionState = 0, crcBLE = 0, bleTestPayload = 0;
 
     int16_t config(uint8_t modem);
+    int16_t setPacketMode(uint8_t mode, uint8_t len);
     int16_t setHeaderType(uint8_t hdrType, size_t len = 0xFF);
 };