diff --git a/README.md b/README.md
index 917f6eb..d91cd05 100644
--- a/README.md
+++ b/README.md
@@ -22,7 +22,7 @@ Please note that this project is released with a [Contributor Code of Conduct](h
 
 * Install [esptool.py](https://github.com/themadinventor/esptool) and make it available on your PATH. If you used esp-open-sdk then this is done already.
 
-* The esp-open-rtos build process uses `GNU Make`, and the utilities `sed` and `grep`. If you built esp-open-sdk then you probably have these already.
+* The esp-open-rtos build process uses `GNU Make`, and the utilities `sed` and `grep`. If you built esp-open-sdk then you have these already.
 
 * Use git to clone the esp-open-rtos project (note the `--recursive`):
 
@@ -38,7 +38,7 @@ cd esp-open-rtos
 #define WIFI_PASS "my secret password"
 ```
 
-Remove the `#warning` and follow the git ignore instructions to keep your credentials from being pushed to Github.
+Remove the `#warning` line and follow the git ignore instructions written in the header file to keep your credentials from being pushed to Github.
 
 * Build an example project (found in the 'examples' directory) and flash it to a serial port:
 
@@ -48,6 +48,8 @@ make flash -j4 -C examples/http_get ESPPORT=/dev/ttyUSB0
 
 Run `make help -C examples/http_get` for a summary of other Make targets.
 
+(Note: the `-C` option to make is the same as changing to that directory, then running make.)
+
 The [Build Process wiki page](https://github.com/SuperHouse/esp-open-rtos/wiki/Build-Process) has in-depth details of the build process.
 
 ## Goals
@@ -57,7 +59,20 @@ The [Build Process wiki page](https://github.com/SuperHouse/esp-open-rtos/wiki/B
 * Leave upstream source clean, for easy interaction with upstream projects.
 * Flexible build and compilation settings.
 
-Current status is alpha quality, under development. AP STATION mode (ie wifi client mode) and UDP/TCP client modes are tested. Other functionality should work. Contributors and testers are welcome!
+Current status is alpha quality, actively developed. AP STATION mode (ie wifi client mode) and UDP/TCP client modes are tested. Other functionality should work. Contributors and testers are welcome!
+
+## Code Structure
+
+* `examples` contains a range of example projects (one per subdirectory). Check them out!
+* `include` contains header files from Espressif RTOS SDK, relating to the binary libraries & Xtensa core.
+* `core` contains source & headers for low-level ESP8266 functions & peripherals. `core/include/esp` contains useful headers for peripheral access, etc. Minimal to no FreeRTOS dependencies.
+* `extras` is a directory that contains optional components that can be added to your project. Most 'extras' components will have a corresponding example in the `examples` directory. Extras include:
+   - i2c - software i2c driver ([upstream project](https://github.com/kanflo/esp-open-rtos-driver-i2c))
+   - rboot-ota - OTA support (over-the-air updates) including a TFTP server for receiving updates ([for rboot by @raburton](http://richard.burtons.org/2015/05/18/rboot-a-new-boot-loader-for-esp8266/))
+   - bmp180 driver for digital pressure sensor ([upstream project](https://github.com/Angus71/esp-open-rtos-driver-bmp180))
+* `FreeRTOS` contains FreeRTOS implementation, subdirectory structure is the standard FreeRTOS structure. `FreeRTOS/source/portable/esp8266/` contains the ESP8266 port.
+* `lwip` and `axtls` contain the lwIP TCP/IP library and the axTLS TLS library ('libssl' in the esp8266 SDKs), respectively. See [Third Party Libraries](https://github.com/SuperHouse/esp-open-rtos/wiki/Third-Party-Libraries) wiki page for details.
+* `libc` contains the newlib libc. [Libc details here](https://github.com/SuperHouse/esp-open-rtos/wiki/libc-configuration).
 
 ## Open Source Components
 
@@ -79,15 +94,6 @@ Some binary libraries appear to contain unattributed open source code:
 * libnet80211.a & libwpa.a appear to be based on FreeBSD net80211/wpa, or forks of them. ([See this issue](https://github.com/SuperHouse/esp-open-rtos/issues/4)).
 * libudhcp has been removed from esp-open-rtos. It was released with the Espressif RTOS SDK but udhcp is GPL licensed.
 
-## Code Structure
-
-* `examples` contains a range of example projects (one per subdirectory). Check them out!
-* `include` contains header files from Espressif RTOS SDK, relating to the binary libraries & Xtensa core.
-* `core` contains source & headers for low-level ESP8266 functions & peripherals. `core/include/esp` contains useful headers for peripheral access, etc. Still being fleshed out. Minimal to no FreeRTOS dependencies.
-* `FreeRTOS` contains FreeRTOS implementation, subdirectory structure is the standard FreeRTOS structure. `FreeRTOS/source/portable/esp8266/` contains the ESP8266 port.
-* `lwip` and `axtls` contain the lwIP TCP/IP library and the axTLS TLS library ('libssl' in the esp8266 SDKs), respectively. See [Third Party Libraries](https://github.com/SuperHouse/esp-open-rtos/wiki/Third-Party-Libraries) wiki page for details.
-
-
 ## Licensing
 
 * BSD license (as described in LICENSE) applies to original source files, [lwIP](http://lwip.wikia.com/wiki/LwIP_Wiki), and [axTLS](http://axtls.sourceforge.net/). lwIP is Copyright (C) Swedish Institute of Computer Science. axTLS is Copyright (C) Cameron Rich.
@@ -98,6 +104,8 @@ Some binary libraries appear to contain unattributed open source code:
 
 * Newlib is covered by several copyrights and licenses, as per the files in the `libc` directory.
 
+Components under `extras/` may contain different licenses, please see those directories for details.
+
 ## Contributions
 
 Contributions are very welcome!
diff --git a/extras/README.md b/extras/README.md
deleted file mode 100644
index 1bc0a52..0000000
--- a/extras/README.md
+++ /dev/null
@@ -1,10 +0,0 @@
-# extras
-
-This folder contains supportive source code.
-
-For current versions or reporting issues etc. please check the main development pages.
-
-- [bmp180](https://github.com/Angus71/esp-open-rtos-driver-bmp180)
-- [i2c](https://github.com/kanflo/esp-open-rtos-driver-i2c)
-- [rboot-ota](http://richard.burtons.org/)
-