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Comment out U-Boot Installation section for now.

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Bradley M. Kuhn 2014-11-07 09:50:06 -05:00
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enforcement-case-studies.tex
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@ -585,59 +585,60 @@ compilation).
%FIXME: dg: can you get me a screen shot for the Kernel Log above, and paste %FIXME: dg: can you get me a screen shot for the Kernel Log above, and paste
%in the output of running busybox ? %in the output of running busybox ?
\section{U-Boot Installation}
The U-Boot installation process is substantially more complicated than the %% \section{U-Boot Installation}
firmware update. The investigator purchased the optional a serial cable
along with the TPE-NWIFIROUTER, in order to complete the U-Boot installation
per the instructions in'' -boot\verb0_0reflash''.
However, we were %% The U-Boot installation process is substantially more complicated than the
only able to read data from the serial port; we were unable to interrupt the %% firmware update. The investigator purchased the optional a serial cable
boot process or access the U-Boot console to complete the U-Boot re-flash. Here %% along with the TPE-NWIFIROUTER, in order to complete the U-Boot installation
are the steps we tried: %% per the instructions in'' -boot\verb0_0reflash''.
* We found the serial cable included was a USB serial adapter that had a male %% However, we were
USB type A connector on one end and 4 female jumper wires at the other end. %% only able to read data from the serial port; we were unable to interrupt the
These female jumper wires were red, black, white, and green. %% boot process or access the U-Boot console to complete the U-Boot re-flash. Here
* The instructions did not specify how to connect these wires, but we were able %% are the steps we tried:
to determine this in part using the "v8.4" image (close to our "v8.2" router)
at \url{http://wiki.openwrt.org/toh/tp-link/tl-wr841nd#serial.console} . Aside from %% * We found the serial cable included was a USB serial adapter that had a male
power and ground (red and black), we did have to guess which of the wires was %% USB type A connector on one end and 4 female jumper wires at the other end.
RX and TX. By experimentation we found that green was RX and white was TX. %% These female jumper wires were red, black, white, and green.
When we tried the other way, we received no data to our serial console at boot %% * The instructions did not specify how to connect these wires, but we were able
time. %% to determine this in part using the "v8.4" image (close to our "v8.2" router)
* We did have to use the included jumper pin gender changer with the USB serial %% at \url{http://wiki.openwrt.org/toh/tp-link/tl-wr841nd#serial.console} . Aside from
adapter, which we put through the holes on the router's mainboard and then %% power and ground (red and black), we did have to guess which of the wires was
connected to the USB serial adapter. The fit was fairly loose so it would be %% RX and TX. By experimentation we found that green was RX and white was TX.
nice if future router versions included a tighter gender changer or (ideally) %% When we tried the other way, we received no data to our serial console at boot
had the jumper pins soldered onto the board to begin with (so no gender %% time.
changer would be required). %% * We did have to use the included jumper pin gender changer with the USB serial
* We used 115200 8N1 as our serial console settings (with no hardware or %% adapter, which we put through the holes on the router's mainboard and then
software flow control). This was tested with both the minicom and screen %% connected to the USB serial adapter. The fit was fairly loose so it would be
commands. We found that if we connected all 4 wires on the USB serial adapter %% nice if future router versions included a tighter gender changer or (ideally)
that the router would start without additional power and our console would %% had the jumper pins soldered onto the board to begin with (so no gender
receive the startup messages. We could replicate the same behavior by %% changer would be required).
omitting the power cable from the USB serial adapter (red wire) and connecting %% * We used 115200 8N1 as our serial console settings (with no hardware or
the main power adapter to the router instead. %% software flow control). This was tested with both the minicom and screen
* While we did see the U-Boot and kernel boot logs in our serial console, we %% commands. We found that if we connected all 4 wires on the USB serial adapter
were unable to interrupt the boot process as u-boot\verb0_0reflash indicated we %% that the router would start without additional power and our console would
should. We suspect this is a misconfiguration of our serial console, but it's %% receive the startup messages. We could replicate the same behavior by
unclear exactly how it is misconfigured, as we were able to receive data fine %% omitting the power cable from the USB serial adapter (red wire) and connecting
(we just couldn't send data to the router). %% the main power adapter to the router instead.
* As a result, we were unable to complete the U-Boot installation test. We did %% * While we did see the U-Boot and kernel boot logs in our serial console, we
appreciate that installation instructions were included, though these %% were unable to interrupt the boot process as u-boot\verb0_0reflash indicated we
instructions should be updated to include more specifics about connecting the %% should. We suspect this is a misconfiguration of our serial console, but it's
serial cable. Since ThinkPenguin does have the option to ship a serial %% unclear exactly how it is misconfigured, as we were able to receive data fine
adapter with the router, it would be helpful if instructions specific to that %% (we just couldn't send data to the router).
adapter were included, as the wiring configuration one should use was unclear. %% * As a result, we were unable to complete the U-Boot installation test. We did
* Additionally, instructions for removing the router's case should be included. %% appreciate that installation instructions were included, though these
We found that the two screws that needed removal to open the case were hidden %% instructions should be updated to include more specifics about connecting the
underneath rubber feet on the case. Indicating which feet need removal to %% serial cable. Since ThinkPenguin does have the option to ship a serial
unscrew the case would be helpful. The instructions should also note that the %% adapter with the router, it would be helpful if instructions specific to that
case needs to be carefully separated once the screws are removed; it %% adapter were included, as the wiring configuration one should use was unclear.
effectively snaps apart, but care must be taken to avoid breaking the plastic %% * Additionally, instructions for removing the router's case should be included.
fasteners that keep the case together after the screws are removed. %% We found that the two screws that needed removal to open the case were hidden
%% underneath rubber feet on the case. Indicating which feet need removal to
%% unscrew the case would be helpful. The instructions should also note that the
%% case needs to be carefully separated once the screws are removed; it
%% effectively snaps apart, but care must be taken to avoid breaking the plastic
%% fasteners that keep the case together after the screws are removed.
\section{Firmware Comparison} \section{Firmware Comparison}