diff --git a/rtos/mbed_lib.json b/rtos/mbed_lib.json
index a062ce3..aed253a 100644
--- a/rtos/mbed_lib.json
+++ b/rtos/mbed_lib.json
@@ -38,18 +38,18 @@
         "STM32L1": {
             "idle-thread-stack-size-debug-extra": 512
         },
-	    "MCU_NRF51": {
-	        "target.boot-stack-size": "0x800"
-	    },
-	    "MCU_NRF52840": {
-	        "target.boot-stack-size": "0x800"
-	    },
-	    "MCU_NRF52832": {
-	        "target.boot-stack-size": "0x800"
-	    },
-	    "MCU_NRF51_UNIFIED": {
-	        "target.boot-stack-size": "0x800"
-	    },
+        "MCU_NRF51": {
+            "target.boot-stack-size": "0x800"
+        },
+        "MCU_NRF52840": {
+            "target.boot-stack-size": "0x800"
+        },
+        "MCU_NRF52832": {
+            "target.boot-stack-size": "0x800"
+        },
+        "MCU_NRF51_UNIFIED": {
+            "target.boot-stack-size": "0x800"
+        },
         "NUVOTON": {
             "idle-thread-stack-size-debug-extra": 512
         }