diff --git a/examples/Makefile-cc2538 b/examples/Makefile-cc2538
index 7bcd64dd1..0b8abe6d8 100644
--- a/examples/Makefile-cc2538
+++ b/examples/Makefile-cc2538
@@ -113,6 +113,10 @@ ifneq ($(CC2538_RECEIVE_SENSITIVITY),)
 COMMONCFLAGS += -DOPENTHREAD_CONFIG_CC2538_RECEIVE_SENSITIVITY=$(CC2538_RECEIVE_SENSITIVITY)
 endif
 
+ifneq ($(CC2538_RSSI_OFFSET),)
+COMMONCFLAGS += -DOPENTHREAD_CONFIG_CC2538_RSSI_OFFSET=$(CC2538_RSSI_OFFSET)
+endif
+
 CPPFLAGS                       += \
     $(COMMONCFLAGS)               \
     $(target_CPPFLAGS)            \
diff --git a/examples/platforms/cc2538/README.md b/examples/platforms/cc2538/README.md
index 64c6d31ae..77675576a 100644
--- a/examples/platforms/cc2538/README.md
+++ b/examples/platforms/cc2538/README.md
@@ -72,6 +72,9 @@ Additional settings can be customised:
 * `CC2538_RECEIVE_SENSITIVITY`: If you have tied the HGM pin to a power rail, this allows
   you to calibrate the RSSI values according to the new receive sensitivity.  This has no
   effect if `CC2592_USE_HGM=1` (the default).
+* `CC2538_RSSI_OFFSET`: If you have tied the HGM pin to a power rail, this allows
+  you to calibrate the RSSI values according to the new RSSI offset.  This has no
+  effect if `CC2592_USE_HGM=1` (the default).
 
 ## Flash Binaries
 
diff --git a/examples/platforms/cc2538/openthread-core-cc2538-config.h b/examples/platforms/cc2538/openthread-core-cc2538-config.h
index 2e08d1b8f..5a468261b 100644
--- a/examples/platforms/cc2538/openthread-core-cc2538-config.h
+++ b/examples/platforms/cc2538/openthread-core-cc2538-config.h
@@ -184,6 +184,22 @@
 #define OPENTHREAD_CONFIG_CC2538_RECEIVE_SENSITIVITY            -88
 #endif
 
+/**
+ * @def OPENTHREAD_CONFIG_CC2538_RSSI_OFFSET
+ *
+ * Set the CC2538 RSSI offset.  This calibrates the RSSI readings received from
+ * the CC2538 radio module to give a reading in dBm.
+ *
+ * For a standard CC2538 (no front-end), the RSSI offset is 73.
+ *
+ * For a CC2592 hard-wired in high-gain mode, an offset of 85 should be used;
+ * or for low-gain mode, 81.  If `OPENTHREAD_CONFIG_CC2592_USE_HGM` is 0, then
+ * this calibrates the RSSI value accordingly.
+ */
+#ifndef OPENTHREAD_CONFIG_CC2538_RSSI_OFFSET
+#define OPENTHREAD_CONFIG_CC2538_RSSI_OFFSET                    73
+#endif
+
 /**
  * @def OPENTHREAD_CONFIG_CC2592_HGM_PORT
  *
diff --git a/examples/platforms/cc2538/radio.c b/examples/platforms/cc2538/radio.c
index 31bb10e82..884433a3e 100644
--- a/examples/platforms/cc2538/radio.c
+++ b/examples/platforms/cc2538/radio.c
@@ -101,17 +101,21 @@ enum
 
 enum
 {
-    CC2538_RSSI_OFFSET  = 73,
-    CC2538_CRC_BIT_MASK = 0x80,
-    CC2538_LQI_BIT_MASK = 0x7f,
+    CC2538_RSSI_OFFSET = OPENTHREAD_CONFIG_CC2538_RSSI_OFFSET,
+    // TI AN130 (SWRA447) Table 4 (bottom of page 3)
+    CC2592_RSSI_OFFSET_HGM = 85,
+    CC2592_RSSI_OFFSET_LGM = 81,
+    CC2538_CRC_BIT_MASK    = 0x80,
+    CC2538_LQI_BIT_MASK    = 0x7f,
 };
 
 // All values in dBm
 enum
 {
-    CC2538_RECEIVE_SENSITIVITY     = OPENTHREAD_CONFIG_CC2538_RECEIVE_SENSITIVITY,
-    CC2592_RECEIVE_SENSITIVITY_LGM = -81,
-    CC2592_RECEIVE_SENSITIVITY_HGM = -85,
+    CC2538_RECEIVE_SENSITIVITY = OPENTHREAD_CONFIG_CC2538_RECEIVE_SENSITIVITY,
+    // TI AN130 (SWRA447) Table 3 (middle of page 3)
+    CC2592_RECEIVE_SENSITIVITY_LGM = -99,
+    CC2592_RECEIVE_SENSITIVITY_HGM = -101,
 };
 
 typedef struct TxPowerTable
@@ -613,6 +617,22 @@ bool otPlatRadioGetPromiscuous(otInstance *aInstance)
     return (HWREG(RFCORE_XREG_FRMFILT0) & RFCORE_XREG_FRMFILT0_FRAME_FILTER_EN) == 0;
 }
 
+static int8_t cc2538RadioGetRssiOffset(void)
+{
+#if OPENTHREAD_CONFIG_CC2538_WITH_CC2592 && OPENTHREAD_CONFIG_CC2592_USE_HGM
+    if (cc2538RadioGetHgm())
+    {
+        return CC2592_RSSI_OFFSET_HGM;
+    }
+    else
+    {
+        return CC2592_RSSI_OFFSET_LGM;
+    }
+#else  // OPENTHREAD_CONFIG_CC2538_WITH_CC2592 && OPENTHREAD_CONFIG_CC2592_USE_HGM
+    return CC2538_RSSI_OFFSET;
+#endif // OPENTHREAD_CONFIG_CC2538_WITH_CC2592 && OPENTHREAD_CONFIG_CC2592_USE_HGM
+}
+
 void otPlatRadioSetPromiscuous(otInstance *aInstance, bool aEnable)
 {
     OT_UNUSED_VARIABLE(aInstance);
@@ -655,7 +675,7 @@ void readFrame(otInstance *aInstance)
         sReceiveFrame.mPsdu[i] = HWREG(RFCORE_SFR_RFDATA);
     }
 
-    sReceiveFrame.mInfo.mRxInfo.mRssi = (int8_t)HWREG(RFCORE_SFR_RFDATA) - CC2538_RSSI_OFFSET;
+    sReceiveFrame.mInfo.mRxInfo.mRssi = (int8_t)HWREG(RFCORE_SFR_RFDATA) - cc2538RadioGetRssiOffset();
     crcCorr                           = HWREG(RFCORE_SFR_RFDATA);
 
     if (crcCorr & CC2538_CRC_BIT_MASK)