Significant improvements to the X200t documentation.

* Clean up of the logical flow of the document a little, better grouping of tablet information.
* Photos of WSON-8 (underside highlighting thermal pad, flashing with cables etc)
* Detail explaining differences in models.
* Detail on how to safely remove WSON-8.
* Link to pre-existing Raspberry Pi instructions.

Signed-off-by: exotime <notabug@exoti.me>

1 files changed, 77 insertions, 17 deletions

diff --git a/docs/install/x200_external.md b/docs/install/x200_external.md
index 16c92662..2eafe7d7 100644
--- a/docs/install/x200_external.md
+++ b/docs/install/x200_external.md
@@ -1,9 +1,12 @@
+
 ---
-title: Flashing the X200 with a BeagleBone Black 
+title: Flashing the X200 with a BeagleBone Black
 ...
 
 Initial flashing instructions for X200.
 
+**Note:** If you are flashing an X200t, [see these alternate instructions](../hardware/x200t_external.html).
+
 This guide is for those who want libreboot on their ThinkPad X200 while
 they still have the original Lenovo BIOS present. This guide can also be
 followed (adapted) if you brick your X200, to know how to recover.
@@ -17,7 +20,7 @@ followed (adapted) if you brick your X200, to know how to recover.
 -   [wwan](#wwan)
 -   [Intel Turbo Memory](#turbomem)
 -   [Memory](#memory)
--   [X200S and X200 Tablet users: GPIO33 trick will not work.](#gpio33)
+-   [X200s and X200t Specific Notes](#x200st)
 
 X200 laptops with libreboot pre-installed {#preinstall}
 =========================================
@@ -33,9 +36,11 @@ Use this to find out:
     # flashrom -p internal -V
 
 The X200S and X200 Tablet will use a WSON-8 flash chip, on the bottom of
-the motherboard (this requires removal of the motherboard). **Not all
-X200S/X200T are supported; see
-[../hardware/x200.html\#x200s](../hardware/x200.html#x200s).**
+the motherboard (this requires removal of the motherboard).
+
+**Not all X200S/X200T are supported; see
+[../hardware/x200.html\#x200s](../hardware/x200.html#x200s) or the additional
+detail at the bottom of this page.**
 
 MAC address {#macaddress}
 ===========
@@ -57,6 +62,10 @@ Initial BBB configuration {#clip}
 Refer to [bbb\_setup.md](bbb_setup.md) for how to set up the BBB for
 flashing.
 
+**Note:** If you don't have a BeagleBone Black, there are instructions for
+[using a Raspberry Pi](./rpi_setup.html) (you may need to adjust them slightly
+for your particular hardware).
+
 The following shows how to connect the clip to the BBB (on the P9
 header), for SOIC-16 (clip: Pomona 5252):
 
@@ -75,6 +84,7 @@ header), for SOIC-16 (clip: Pomona 5252):
     Here is a photo of the SOIC-16 flash chip. Pins are labelled:
 
 
+
 The following shows how to connect the clip to the BBB (on the P9
 header), for SOIC-8 (clip: Pomona 5250):
 
@@ -91,19 +101,13 @@ header), for SOIC-8 (clip: Pomona 5250):
     Look at the pads in that photo, on the left and right. Those are for SOIC-16. Would it be possible to remove the SOIC-8 and solder a SOIC-16
     chip on those pins?
 
-**On the X200S and X200 Tablet the flash chip is underneath the board,
-in a WSON package. The pinout is very much the same as a SOIC-8, but such package makes it impossible to use testclip.
-In order to enable external flashing of device, chip has to be changed to SOIC-8 one. Such procedure requires hot air station and soldering station (with "knife" K-Tip to easily solder SOIC-8).\
-Check the list of SOIC-8 flash chips at
-[List of supported flash chips](https://www.flashrom.org/Supported_hardware#Supported_flash_chips)\
-25XX series SPI NOR Flash in 8/16MiB sizes will work fine with libreboot.
 
 The procedure
 -------------
 
-This section is for the X200. This does not apply to the X200S or X200
-Tablet (for those systems, you have to remove the motherboard
-completely, since the flash chip is on the other side of the board).
+This section is for the X200. This does not apply to the X200S or X200 Tablet
+(for those systems, you have to remove the motherboard completely, since the
+flash chip is on the other side of the board. See below for more information).
 
 Remove these screws:\
 ![](images/x200/disassembly/0003.jpg)
@@ -248,7 +252,13 @@ Not to be confused with wifi (wifi is fine).
 Intel Turbo Memory {#turbomem}
 ==================
 
-Some X200 devices were sold with Intel Turbo Memory installed in the top-most mini PCI-e slot. This has been [shown to be ineffective](http://www.anandtech.com/show/2252) at disk caching or battery saving in most use cases. While there are [Linux drivers](https://github.com/yarrick/turbomem) available, it is blacklisted in at least GNU+Trisquel, and possibly other free operating systems. It should probably be removed.
+Some X200 devices were sold with Intel Turbo Memory installed in the top-most
+mini PCI-e slot. This has been [shown to be
+ineffective](http://www.anandtech.com/show/2252) at disk caching or battery
+saving in most use cases. While there are [Linux
+drivers](https://github.com/yarrick/turbomem) available, it is blacklisted in at
+least GNU+Trisquel, and possibly other free operating systems. It should
+probably be removed.
 
 Memory
 ======
@@ -274,8 +284,58 @@ You should see something like this:
 
 Now [install GNU+Linux](../gnulinux/).
 
-X200S and X200 Tablet users: GPIO33 trick will not work. {#gpio33}
---------------------------------------------------------
+
+X200s and X200t Specific Notes {#x200st}
+==============================
+
+Chip Differences
+----------------
+Most notably, the BIOS chip is on the other side of the motherboard when
+compared to the X200. It is also a slightly different form factor (WSON-8)
+compared to the X200 (SOIC-8). The implication of this is that there is no clip
+that can touch the tiny pins on the outside, so you'll either need to solder
+wires to the chip (very difficult, but not impossible) or remove the chip
+entirely. Note that there is a large thermal pad under the WSON-8 chip, which
+makes it quite difficult to remove as it removes the heat you are applying.
+Using a hot air gun, set the temperature to around 400 degrees Celcius and
+gently heat the part evenly (it will not budge no matter how patient and careful
+you are at a normally advisable 300-350C). Applying some Chip Quik (or similar)
+will make removal easier. On the X200t especially, be careful of R647 in
+immediate proximity to the flash chip.
+
+Once the chip has been removed from the motherboard, it can be replaced with a
+suitable SOIC-8 that supports a clip.
+
+See the following images for reference:
+
+![](../../docs/images/x200t_flash/X200T-flashchip-location.jpg)
+![](../../docs/images/x200t_flash/X200T-flashchip-underside.jpg)
+
+If you choose to solder directly to the chip, you will probably have more
+success using Kynar wire-wrapping wire (or similar). Secure the flyleads with
+hot glue to prevent them from pulling off.
+
+![](../../docs/images/x200t_flash/X200T-reflashing-onboard.jpg)
+
+If you intend on flashing the chip (either the WSON-8 or the SOIC-8) off the
+motherboard, you need to pull the HOLD pin to +3.3V. Leaving it floating will
+result in inconsistent writes as it bounces around. The motherboard does this by
+default. Some chips you will also need to pull the WP pin to +3.3V, but on
+others it is not necessary (check the datasheet for your specific chip,
+depending if they default to LOW or HIGH).
+
+![](../../docs/images/x200t_flash/X200T-reflashing-offboard.jpg)
+
+
+Suitable WSON-8 Replacements
+----------------------------
+Check the list of SOIC-8 flash chips at [List of supported flash
+chips](https://www.flashrom.org/Supported_hardware#Supported_flash_chips)\ 25XX
+series SPI NOR Flash in 8/16MiB sizes will work fine with libreboot.
+
+
+GPIO33 trick will not work. {#gpio33}
+---------------------------
 
 sgsit found out about a pin called GPIO33, which can be grounded to
 disable the flashing protections by the descriptor and stop the ME from