diff --git a/README.md b/README.md
index 8260283..2869342 100644
--- a/README.md
+++ b/README.md
@@ -1,8 +1,8 @@
-About
+About
 =====
 
 This is Arduino add-on package for NXP JN516x platform.
-This version is built on [Contiki](http://contiki-os.org/).
+This package is built on [ContikiOS](http://contiki-os.org/).
 
 Install
 =======
@@ -16,106 +16,26 @@ Use this additional package definition of 'Additional Boards Manager URLs' optio
 Install Compiler and SDK.
 ----------------------------
 
-Download and install compiler, sdk and flash programmer from [ NXP's JN516x page](https://www.nxp.com/products/wireless-connectivity/proprietary-ieee-802.15.4-based/ieee-802.15.4-for-jn516x-7x:IEEE802.15.4).
+Download and install compiler and sdk from [NXP's JN516x page](https://www.nxp.com/products/wireless-connectivity/proprietary-ieee-802.15.4-based/ieee-802.15.4-for-jn516x-7x:IEEE802.15.4).
 
-* [BeyondStudio for NXP](https://cache.nxp.com/secured/sdk/JN-SW-4141.zip?__gda__=1529072216_c38bbf7395e570fc9b3c09578d634af9&fileExt=.zip)
+* `JN-SW-4141` BeyondStudio for NXP 
+* `JN-SW-4163` JN516x IEEE 802.15.4 SDK
 
-* [JN516x IEEE 802.15.4 SDK](https://cache.nxp.com/secured/sdk/JN-SW-4163.zip?__gda__=1529072150_ac3fdfa99c6ad205b36cb1c932c56441&fileExt=.zip)
+### For Windows
 
-* [JN51xx Producton Flash Programmer](https://www.nxp.com/downloads/en/software-support/JN-SW-4107.zip)
+Install `JN-SW-4141` and `JN-SW-4163` to installer's default destination (C:\NXP).
 
+### For Linux/MacOSX
 
-### For Windows
+Install *JN516x IEEE 802.15.4 SDK* contents (JN-SW-4163 directory, need to extract on windows) under `/usr/jn516x-sdk/`(default directory as Contiki expects).
+If installed to another directory, set the path to `SDK_BASE_DIR` and export it.
 
-Install to installer's default destination (C:\NXP).
 
-### For Linux/MacOSX
+Limitations
+===========
 
-Install [JN516x IEEE 802.15.4 SDK](http://cache.nxp.com/documents/other/JN-SW-4163.zip) 
-contents (JN-SW-4163 directory, need to extract on windows) place under `/usr/jn516x-sdk/`.
-
-API implements status
-====================
-
-Already implemented
--------------------
-### Digital I/O
-- pinMode()
-- digitalWrite()
-- digitalRead()
-
-### Analog I/O
-- analogReference()
-- analogRead()
-- analogWrite()
-
-### Advanced I/O
-- shiftOut()
-- shiftIn()
-
-### Time
-- millis()
-- micros()
-- delay()
-
-### Math
-- min()
-- max()
-- abs()
-- constrain()
-- map()
-- pow()
-- sqrt()
-
-### Trigonometry
-- sin()
-- cos()
-- tan()
-
-### Random Numbers
-- randomSeed()
-- random()
-
-### Bits and Bytes
-- lowByte()
-- highByte()
-- bitRead()
-- bitWrite()
-- bitSet()
-- bitClear()
-- bit()
-
-### Interrupts
-- interrupts()
-- noInterrupts()
-
-### External Interrupts
-- attachInterrupt()
-- detachInterrupt()
-
-### Communication
-- Serial
-- Stream
-
-Not implemented yet.
---------------------
-
-### Time
-- delayMicroseconds()
-
-### Advanced I/O
-- tone() _This function will follow the implementation status of Arduino Due._
-- noTone() _This function will follow the implementation status of Arduino Due._
-- pulseIn() _System dependent constants are not tuned._
-
-### stdlib
-
-- malloc()
-- free()
-
-Limitation by Hardware difference
-=================================
 ### Not support function.
+
 - analogReadResolution()
 - analogWriteResolution()
 - Keyboard