Project

General

Profile

D-Link DWM-222 stick » History » Version 2

domi, 08/15/2018 07:16 PM

1 1 domi
h1. D-Link DWM-222 stick
2
3
!{width:300px}dwm222_pic.jpg!
4
5
This stick is available at multiple operators and it is quite cheap. If you want to get into Linux-based Qualcomm dongles that are easier to attach to your laptop than Quectel modems it might be a way to go.
6
*WARNING!
7
Current version of the DWM-222 does NOT expose ADB, so accessing the underlying Linux is currently not possible! HOWEVER there might be ways to enable this functionality, so keep reading, but BE AWARE BEFORE PUCHASING!*
8
9
It is just a D-Link branded version of cheaper dongles made in China. Some of them are WiFi access points with LTE backhaul using [[QCMAP]].
10
Example of devices that are closely related:
11
* PTCL Charji Wingle R660
12
* (?)D-Link DWR 901 (unsure, FIXME)
13
14
15
h2. Hardware
16
17
!{width:500px}pcb_pic.jpg!
18
19
Opening the stick requires just removing the back cover (which reveals the standard size SIM slot and the microSD card reader), then unscrewing the 3 screws.
20
The stick is based on the Qualcomm MDM9225 chipset. It is closely related to the MDM9625 apparently (based on the firmware analysis).
21
There are two antenna connectors (U.FL) exposed on the PCB.
22
23
h2. Software
24
25
The dongle is a typical USB WWAN modem. It requires usb_modeswitch to change from mass_storage mode (enables installation of driver) to modem mode.
26
Mass storage mode USB id: *2001:ab00*
27
WWAN USB id: *2001:7e35*
28
29
After the switch you'll see 4 @ttyUSB@ devices appearing in @/dev@. For me these devices only started to work after telling the @option@ driver about the USB id of the device:
30
<pre>
31
echo "2001 7e35" > /sys/bus/usb-serial/drivers/option1/new_id
32
</pre>
33
34
The devices are:
35
<pre>
36
/dev/ttyUSB0  --> DIAG
37
/dev/ttyUSB1  --> AT commands
38
/dev/ttyUSB2
39
/dev/ttyUSB3
40
/dev/cdc-wdm0 --> QMI
41
</pre>
42
43
h3. Drivers
44
45
If in mass_storage mode there is a Windows driver available with D-Link Connection Manager. It basically just switches the device to modem mode, and then provides a GUI to establish a connection.
46
Surprisingly D-Link provides Linux support for the dongle. A page is dedicated to guide you through the installation. https://eu.dlink.com/uk/en/support/faq/routers/mobile-routers/how-to-install-my-dwm-222-on-ubuntu
47
However it is not recommended to follow the instructions, because the 'driver' is just a collection of bash scripts that tries to configure PPP daemon. Interestingly it has a complete collection of MCC, MNC, APN triples for all operators around the world. Based on the IMSI queried from the SIM card it tries to find the right settings and feed them to pppd.
48
49
h2. Firmware
50
51
There are 2 firmware versions available for download currently: 2.0.1 and 2.0.8. https://eu.dlink.com/uk/en/products/dwm-222-4g-lte-usb-adapter#support
52
The dongle that I had came with an older version, 1.7.9. It doesn't really work for me, so I upgraded to 2.0.8:
53
54
h3. Upgrade process
55
56
Upgrade can only be done from Windows. The file provided is a self-extracting executable. After extracting the contents it turned out to be quite interesting: a collection of executables and batch files, as well as MBN and yaffs2 images.
57
After tracing the upgrade process I've established its steps roughly:
58
59
<pre>
60
Start 1key.bat -> Installs drivers (ADB, QDLoader, Fastboot) -> Runs dl.exe -> Device goes into QDL mode -> MBN files are flashed -> Device reboots.
61
</pre>
62
63
Now comes the tricky part: the bat files tries to reboot the device into @fastboot@ mode using ADB shell. However D-Link requested ADB to be turned off for the device, so the @fastboot@ part fails. Basically you'll end up with a device that has new DSP software, but the Android part is unchanged. Fortunately the device stays operational after the failed update, only its LED is stuck on white instead of different colors/blinking.
64
So the complete upgrade cycle would look like this (based on reading the bat files):
65
66
<pre>
67
Start 1key.bat -> Installs drivers (ADB, QDLoader, Fastboot) -> Runs dl.exe -> Device goes into QDL mode -> MBN files are flashed -> Device reboots
68
-> ADB shell to reboot into fastboot mode -> Android images are flashed using fastboot (rootfs, usr) -> Device rebooted again, check if it is not stuck in bootloader -> Done.
69
</pre>
70
71
h3. Analyzing the firmware
72
73
Since it is just YAFFS2 it was easy to unpack the firmware and poke around it. No encryption/signatures/etc. was in place.
74
It is, as suspected, Linux.
75 2 domi
They supply 2 YAFFS2 images: one is the @rootfs@, the other is @/usr@
76 1 domi
77 2 domi
File list of @rootfs@
78
79 1 domi
<pre>
80
# ls -lha
81
total 84K
82
drwxr-xr-x 20 root root 4,0K aug   10 14:58 .
83
drwxr-xr-x  5 root root 4,0K aug   10 15:30 ..
84
drwxr-xr-x  2 root root 4,0K aug   10 14:58 bin
85
drwxr-xr-x  2 root root 4,0K aug   10 14:58 boot
86
-rw-r--r--  1 root root   47 aug   10 14:58 build.prop
87
drwxr-xr-x  2 root root 4,0K aug   10 14:58 cache
88
drwxr-xr-x  2 root root 4,0K aug   10 14:58 dev
89
drwxr-xr-x 30 root root 4,0K aug   10 14:58 etc
90
drwxr-xr-x  3 root root 4,0K aug   10 14:58 home
91
drwxr-xr-x  5 root root 4,0K aug   10 14:58 lib
92
lrwxrwxrwx  1 root root   12 aug   10 14:58 linuxrc -> /bin/busybox
93
drwxr-xr-x 10 root root 4,0K aug   10 14:58 media
94
drwxr-xr-x  2 root root 4,0K aug   10 14:58 mnt
95
drwxr-xr-x  2 root root 4,0K aug   10 14:58 proc
96
drwxr-xr-x  2 root root 4,0K aug   10 14:58 sbin
97
lrwxrwxrwx  1 root root   11 aug   10 14:58 sdcard -> /media/card
98
drwxr-xr-x  3 root root 4,0K aug   10 14:58 share
99
drwxr-xr-x  2 root root 4,0K aug   10 14:58 sys
100
drwxr-xr-x  2 root root 4,0K aug   10 14:58 tmp
101
drwxr-xr-x  2 root root 4,0K aug   10 14:58 usr
102
drwxr-xr-x  8 root root 4,0K aug   10 14:58 var
103
drwxr-xr-x  3 root root 4,0K aug   10 14:58 WEBSERVER
104
drwxr-xr-x  5 root root 4,0K aug   10 14:58 www
105
</pre>
106
107 2 domi
The @WEBSERVER@ and @www@ directory are there for the WiFi router versions which use a web-based interface for settings.
108 1 domi
109
I was mainly curious about ADB, so I followed the @/etc/init.d/usb@ script. It saves the USB device id of the device to a file, then based on the id it starts a bash script located in @/usr/bin/usb/compositions@
110
111
<pre>
112
ls -lha bin/usb/compositions/
113
total 228K
114
drwxr-xr-x 2 root root 4,0K aug   10 14:58 .
115
drwxr-xr-x 3 root root 4,0K aug   10 14:28 ..
116
-rw-r--r-- 1 root root 3,8K aug   10 14:28 2033
117
-rw-r--r-- 1 root root 4,0K aug   10 14:28 2034
118
-rw-r--r-- 1 root root 4,4K aug   10 14:28 2037
119
-rw-r--r-- 1 root root 3,8K aug   10 14:28 3443
120
-rw-r--r-- 1 root root 4,4K aug   10 14:28 3444
121
-rw-r--r-- 1 root root 4,4K aug   10 14:28 4030
122
-rw-r--r-- 1 root root 3,8K aug   10 14:58 7e35
123
-rw-r--r-- 1 root root 4,6K aug   10 14:28 7e35A
124
-rw-r--r-- 1 root root 4,4K aug   10 14:28 7e37
125
-rw-r--r-- 1 root root 4,4K aug   10 14:28 7e38
126
-rw-r--r-- 1 root root 4,4K aug   10 14:28 7e39
127
-rw-r--r-- 1 root root 4,4K aug   10 14:28 7e3c
128
-rw-r--r-- 1 root root 3,8K aug   10 14:28 7e3d
129
-rw-r--r-- 1 root root 2,3K aug   10 14:28 9002
130
-rw-r--r-- 1 root root 2,2K aug   10 14:28 901C
131
-rw-r--r-- 1 root root 2,8K aug   10 14:28 901D
132
-rw-r--r-- 1 root root 3,4K aug   10 14:28 9021
133
-rw-r--r-- 1 root root 3,4K aug   10 14:28 9022
134
-rw-r--r-- 1 root root 2,7K aug   10 14:28 9024
135
-rw-r--r-- 1 root root 3,6K aug   10 14:28 9025
136
-rw-r--r-- 1 root root 3,5K aug   10 14:28 9026
137
-rw-r--r-- 1 root root 2,7K aug   10 14:28 902A
138
-rw-r--r-- 1 root root 2,7K aug   10 14:28 902B
139
-rw-r--r-- 1 root root 2,7K aug   10 14:28 902C
140
-rw-r--r-- 1 root root 2,8K aug   10 14:28 902D
141
-rw-r--r-- 1 root root 3,9K aug   10 14:28 902E
142
-rw-r--r-- 1 root root 3,3K aug   10 14:28 9043
143
-rw-r--r-- 1 root root 3,0K aug   10 14:28 9046
144
-rw-r--r-- 1 root root 2,4K aug   10 14:28 9047
145
-rw-r--r-- 1 root root 3,5K aug   10 14:28 9049
146
-rw-r--r-- 1 root root 2,2K aug   10 14:28 904A
147
-rw-r--r-- 1 root root 3,6K aug   10 14:28 9056
148
-rw-r--r-- 1 root root 2,7K aug   10 14:28 9057
149
-rw-r--r-- 1 root root 2,9K aug   10 14:28 9059
150
-rw-r--r-- 1 root root 3,2K aug   10 14:28 905A
151
-rw-r--r-- 1 root root 3,0K aug   10 14:28 905B
152
-rw-r--r-- 1 root root 2,2K aug   10 14:28 9060
153
-rw-r--r-- 1 root root 3,2K aug   10 14:28 9063
154
-rw-r--r-- 1 root root 4,4K aug   10 14:28 9064
155
-rw-r--r-- 1 root root 4,0K aug   10 14:28 9067
156
-rw-r--r-- 1 root root 3,0K aug   10 14:28 9083
157
-rw-r--r-- 1 root root 3,0K aug   10 14:28 9084
158
-rw-r--r-- 1 root root 3,1K aug   10 14:28 9085
159
-rw-r--r-- 1 root root  127 aug   10 14:28 empty
160
-rw-r--r-- 1 root root    2 aug   10 14:28 hsic_next
161
-rw-r--r-- 1 root root    5 aug   10 14:28 hsusb_next
162
</pre>
163
164
Looking into the file @7e35@ (the id of the D-Link device) reveals why ADB is missing - the Android USB Gadget is configured without ADB:
165
166
<pre>
167
# cat bin/usb/compositions/7e35
168
169
#!/bin/sh
170
#
171
# Copyright (c) 2012, The Linux Foundation. All rights reserved.
172
#
173
# Redistribution and use in source and binary forms, with or without
174
# modification, are permitted provided that the following conditions are met:
175
#     * Redistributions of source code must retain the above copyright
176
#       notice, this list of conditions and the following disclaimer.
177
#     * Redistributions in binary form must reproduce the above copyright
178
#       notice, this list of conditions and the following disclaimer in the
179
#       documentation and/or other materials provided with the distribution.
180
#     * Neither the name of The Linux Foundation nor the names of its
181
#       contributors may be used to endorse or promote products derived from
182
#       this software without specific prior written permission.
183
#
184
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
185
# INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY,
186
# FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE DISCLAIMED.  IN NO
187
# EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
188
# INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
189
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
190
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
191
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
192
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
193
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
194
195
# DESCRIPTION: DIAG + MODEM + AT + NMEA + QMI_RMNET + ADB + Mass Storage (Android)
196
197
echo "Switching to composition number 0x7e35"
198
199
if [ "$1" = "y" ]; then
200
	num="1"
201
else
202
	num="0"
203
fi
204
205
echo 0 > /sys/class/android_usb/android$num/enable
206
if [ "$2" = "y" ]; then 
207
	echo 0xAB00 > /sys/class/android_usb/android$num/idProduct
208
	echo 0x2001 > /sys/class/android_usb/android$num/idVendor
209
	echo mass_storage > /sys/class/android_usb/android$num/functions
210
	echo 1 > /sys/class/android_usb/android$num/enable
211
else
212
	run_9x15() {
213
		echo 0x7e35 > /sys/class/android_usb/android$num/idProduct
214
		echo 0x2001 > /sys/class/android_usb/android$num/idVendor
215
		echo diag > /sys/class/android_usb/android0/f_diag/clients
216
		echo smd,smd,tty > /sys/class/android_usb/android0/f_serial/transports
217
		echo SMD,BAM2BAM > /sys/class/android_usb/android0/f_rmnet/transports
218
		echo diag,serial,rmnet,mass_storage > /sys/class/android_usb/android$num/functions
219
 		echo 1 > /sys/class/android_usb/android$num/enable
220
  	}
221
222
	run_9x25() {
223
		echo 0x7e35 > /sys/class/android_usb/android$num/idProduct
224
		echo 0x2001 > /sys/class/android_usb/android$num/idVendor
225
		echo diag > /sys/class/android_usb/android0/f_diag/clients
226
		echo smd,smd,tty > /sys/class/android_usb/android0/f_serial/transports
227
		echo SMD,BAM2BAM_IPA > /sys/class/android_usb/android0/f_rmnet/transports
228
		echo diag,serial,rmnet,mass_storage > /sys/class/android_usb/android$num/functions
229
 		echo 1 > /sys/class/android_usb/android$num/enable
230
	}
231
232
	run_9x25_v2() {
233
		echo 0x7e35 > /sys/class/android_usb/android$num/idProduct
234
		echo 0x2001 > /sys/class/android_usb/android$num/idVendor
235
		echo 0123456789ABCDEF > /sys/class/android_usb/android$num/iSerial
236
		echo diag > /sys/class/android_usb/android0/f_diag/clients
237
		echo smd,smd,tty > /sys/class/android_usb/android0/f_serial/transports
238
		echo QTI,BAM2BAM_IPA > /sys/class/android_usb/android0/f_rmnet/transports
239
		echo diag,serial,rmnet,mass_storage > /sys/class/android_usb/android$num/functions
240
 		echo 1 > /sys/class/android_usb/android$num/enable
241
	}
242
243
	case `source /usr/bin/usb/target` in
244
		*9x15* )
245
			run_9x15 &
246
			;;
247
		*9x25* )
248
			case `cat /sys/devices/soc0/revision` in
249
				*1.0* )
250
					run_9x25 &
251
					;;
252
				*2.* )
253
					run_9x25_v2 &
254
					;;
255
				* )
256
					run_9x25 &
257
					;;
258
			esac
259
			;;
260
		* )
261
			run_9x15 &
262
			;;
263
  	esac
264
fi
265
266
</pre>
267
268 2 domi
Simple adding @adb@ to the echos should be enough, based on the other script files. So I added the string @adb@ to the right places in the file, re-packed the @usr@ YAFFS2 image just to find out that because I could not get it into fastboot mode...so if someone could find a way to put the dongle into fastboot mode then simply installing a patched firmware file would enable ADB on the device.
269 1 domi
270
So now the question arises: what kind of dongle would you need to buy that has ADB out of the box? I could tell you the USB device id of such devices:
271
272
<pre>
273
grep -r adb .
274
./905A:	echo diag,adb,usb_mbim:ecm_qc > /sys/class/android_usb/android$num/functions
275
./905A:	echo diag,adb,usb_mbim:ecm_qc > /sys/class/android_usb/android$num/functions
276
./9025:	echo diag,adb,serial,rmnet,mass_storage > /sys/class/android_usb/android$num/functions
277
./9025:	echo diag,adb,serial,rmnet,mass_storage > /sys/class/android_usb/android$num/functions
278
./9025:	echo diag,adb,serial,rmnet,mass_storage > /sys/class/android_usb/android$num/functions
279
./9022:	echo diag,adb,rmnet > /sys/class/android_usb/android$num/functions
280
./9022:	echo diag,adb,rmnet > /sys/class/android_usb/android$num/functions
281
./9022:	echo diag,adb,rmnet > /sys/class/android_usb/android$num/functions
282
./9059:	echo rndis_qc,diag,adb:ecm_qc > /sys/class/android_usb/android$num/functions
283
./9059:	echo rndis,diag,adb:ecm_qc > /sys/class/android_usb/android$num/functions
284
./9064:	echo diag,adb,serial,rmnet:ecm_qc:usb_mbim > /sys/class/android_usb/android$num/functions
285
./9064:	echo diag,adb,serial,rmnet:ecm:usb_mbim > /sys/class/android_usb/android$num/functions
286
./9064:	echo diag,adb,serial,rmnet:ecm_qc:usb_mbim > /sys/class/android_usb/android$num/functions
287
./9046:	echo diag,adb,serial,rmnet,mass_storage > /sys/class/android_usb/android$num/functions
288
./9046:	echo diag,adb,serial,rmnet,mass_storage > /sys/class/android_usb/android$num/functions
289
./9024:	echo rndis_qc,adb > /sys/class/android_usb/android$num/functions
290
./9024:	echo rndis,adb > /sys/class/android_usb/android$num/functions
291
./9049:	echo diag,adb,serial,rmnet,mass_storage,qdss > /sys/class/android_usb/android$num/functions
292
./9049:	echo diag,adb,serial,rmnet,mass_storage,qdss > /sys/class/android_usb/android$num/functions
293
./9049:	echo diag,adb,serial,rmnet,mass_storage,qdss > /sys/class/android_usb/android$num/functions
294
./902D:	echo rndis_qc,diag,adb > /sys/class/android_usb/android$num/functions
295
./902D:	echo rndis,diag,adb > /sys/class/android_usb/android$num/functions
296
./901D:	echo diag,adb > /sys/class/android_usb/android$num/functions
297
./901D:	echo diag,adb > /sys/class/android_usb/android$num/functions
298
./9084:	echo diag,qdss,adb,rmnet > /sys/class/android_usb/android$num/functions
299
./9084:	echo diag,qdss,adb,rmnet > /sys/class/android_usb/android$num/functions
300
./902B:	echo rndis_qc,adb,mass_storage > /sys/class/android_usb/android$num/functions
301
./902B:	echo rndis,adb,mass_storage > /sys/class/android_usb/android$num/functions
302
./9085:	echo diag,adb,usb_mbim,gps > /sys/class/android_usb/android$num/functions
303
./9085:	echo diag,adb,usb_mbim,gps > /sys/class/android_usb/android$num/functions
304
./2034:	echo rndis_qc,diag,serial,adb,mass_storage > /sys/class/android_usb/android$num/functions
305
./2034:	echo rndis,diag,serial,adb,mass_storage > /sys/class/android_usb/android$num/functions
306
./2034:	echo rndis,diag,serial,adb,mass_storage > /sys/class/android_usb/android$num/functions
307
./9060:	echo diag,qdss,adb > /sys/class/android_usb/android$num/functions
308
./9056:	echo diag,adb,serial,rmnet,mass_storage,audio > /sys/class/android_usb/android$num/functions
309
./9056:	echo diag,adb,serial,rmnet,mass_storage,audio > /sys/class/android_usb/android$num/functions
310
./9056:	echo diag,adb,serial,rmnet,mass_storage,audio > /sys/class/android_usb/android$num/functions
311
</pre>
312
313 2 domi
It would be great to find out the actual vendor of these, so we can tell people exactly what to buy. I'm assuming Chinese LTE dongles from eBay are prime candidates, but that's just a guess.
Add picture from clipboard (Maximum size: 48.8 MB)