This page describes pre‑prelease version of usb armory, so if you are receiving release version,
 head over to usb armory wiki https://github.com/f‑secure‑foundry/usbarmory/wiki  which improved massively 
 since this page was first written.
I had wrong expectations from this board: I was hoping to be able to use GPIO for serial or connecting sensors and that is not possible.

Contents: [Dobrica Pavlinušić's random unstructured stuff]
• Dobrica Pavlinušić's random unstructured stuff (network setup) 
• Dobrica Pavlinušić's random unstructured stuff (boot select switch) 
• Dobrica Pavlinušić's random unstructured stuff (image delivered on device) 
• Dobrica Pavlinušić's random unstructured stuff (pads on board) 
• Dobrica Pavlinušić's random unstructured stuff (sdcard vs emmc speed) 
• Dobrica Pavlinušić's random unstructured stuff (community) 
• Dobrica Pavlinušić's random unstructured stuff (led heartbeat off) 
• Dobrica Pavlinušić's random unstructured stuff (network speed) 
• Dobrica Pavlinušić's random unstructured stuff (network setup for desktop) 
• Dobrica Pavlinušić's random unstructured stuff (bluetooth) 
• Dobrica Pavlinušić's random unstructured stuff (armoryctl) 
• Dobrica Pavlinušić's random unstructured stuff (i2c) 

SoC: NXP i.MX6ULZ ARM® Cortex™‑A7 900 MHz
 RAM: 512 MB DDR3
 Storage: internal 16 GB eMMC + external microSD
 Bluetooth module: u‑blox ANNA‑B112 BLE
 USB‑C ports: DRP (Dual Role Power) receptacle + UFP (Upstream Facing Port) plug, USB 2.0 only (no video support)
 LEDs: two
 Slide switch: for boot mode selection between eMMC and microSD
 External security elements: Microchip ATECC608A + NXP A71CH
 Physical size: 66 mm x 19 mm x 8 mm (without enclosure, including USB‑C connector)
https://github.com/inversepath/usbarmory‑debian‑base_image 
dpavlin@klin:~/usb-armory/usbarmory-debian-base_image$ ls -al usbarmory-mark-two-debian_stretch-base_image-20191013.raw
-rw-r--r-- 1 root root 3670016000 Oct 13 13:30 usbarmory-mark-two-debian_stretch-base_image-20191013.raw

dpavlin@nuc:/mnt/klin/home/dpavlin/usb-armory/usbarmory-debian-base_image$ dd if=usbarmory-mark-two-debian_stretch-base_image-20191013.raw of=/dev/sdb bs=1M

dpavlin@nuc:~$ dmesg
[764607.538898] usb 2-1: new high-speed USB device number 34 using xhci_hcd
[764607.689068] usb 2-1: New USB device found, idVendor=0525, idProduct=a4a2, bcdDevice= 4.19
[764607.689078] usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[764607.689082] usb 2-1: Product: RNDIS/Ethernet Gadget
[764607.689100] usb 2-1: Manufacturer: Linux 4.19.78-0 with 2184000.usb
[764607.900916] cdc_subset: probe of 2-1:1.0 failed with error -22
[764607.902622] cdc_subset 2-1:1.1 usb0: register 'cdc_subset' at usb-0000:00:14.0-1, Linux Device, ae:47:47:81:a0:a4
[764607.902666] usbcore: registered new interface driver cdc_subset
[764607.902711] cdc_ether: probe of 2-1:1.0 failed with error -16
[764607.902732] usbcore: registered new interface driver cdc_ether
[764607.914234] cdc_subset 2-1:1.1 enp0s20u1i1: renamed from usb0

network setup
dpavlin@nuc:~$ sudo ifconfig enp0s20u1i1 10.0.0.2 netmask 255.255.255.0

dpavlin@nuc:~$ sudo iptables -t nat -A POSTROUTING -s 10.0.0.0/24 -o eth0 -j MASQUERADE

dpavlin@nuc:~$ ssh usbarmory@10.0.0.1
# password is usbarmory

usbarmory@usbarmory:~$ uname -a
Linux usbarmory 4.19.78-0 #1 PREEMPT Sun Oct 13 11:05:18 UTC 2019 armv7l GNU/Linux
usbarmory@usbarmory:~$ cat /proc/cpuinfo
processor       : 0
model name      : ARMv7 Processor rev 5 (v7l)
BogoMIPS        : 109.09
Features        : half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae
CPU implementer : 0x41
CPU architecture: 7
CPU variant     : 0x0
CPU part        : 0xc07
CPU revision    : 5

Hardware        : Freescale i.MX6 Ultralite (Device Tree)
Revision        : 0000
Serial          : 0000000000000000
usbarmory@usbarmory:~$ free
              total        used        free      shared  buff/cache   available
Mem:         512204       25588      436744        7624       49872      467984
Swap:             0           0           0

boot select switch
Switch near sdcard select booting from emmc or microsd (silkscreen is somewhat poor, but by default bafore removing sticker it will boot from sdcard)
If it's closer to sdcard, it will boot from sdcard
image delivered on device
Password for image delivered with device is not usbarmory (?)
In fact, it doesn't have usbarmory user in /etc/passwd, but has it in /etc/shadow, go figure!
root@usbarmory:/# cat /etc/passwd
root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
bin:x:2:2:bin:/bin:/usr/sbin/nologin
sys:x:3:3:sys:/dev:/usr/sbin/nologin
sync:x:4:65534:sync:/bin:/bin/sync
games:x:5:60:games:/usr/games:/usr/sbin/nologin
man:x:6:12:man:/var/cache/man:/usr/sbin/nologin
lp:x:7:7:lp:/var/spool/lpd:/usr/sbin/nologin
mail:x:8:8:mail:/var/mail:/usr/sbin/nologin
news:x:9:9:news:/var/spool/news:/usr/sbin/nologin
uucp:x:10:10:uucp:/var/spool/uucp:/usr/sbin/nologin
proxy:x:13:13:proxy:/bin:/usr/sbin/nologin
www-data:x:33:33:www-data:/var/www:/usr/sbin/nologin
backup:x:34:34:backup:/var/backups:/usr/sbin/nologin
list:x:38:38:Mailing List Manager:/var/list:/usr/sbin/nologin
irc:x:39:39:ircd:/var/run/ircd:/usr/sbin/nologin
gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/usr/sbin/nologin
nobody:x:65534:65534:nobody:/nonexistent:/usr/sbin/nologin
systemd-timesync:x:100:102:systemd Time Synchronization,,,:/run/systemd:/bin/false
systemd-network:x:101:103:systemd Network Management,,,:/run/systemd/netif:/bin/false
systemd-resolve:x:102:104:systemd Resolver,,,:/run/systemd/resolve:/bin/false
systemd-bus-proxy:x:103:105:systemd Bus Proxy,,,:/run/systemd:/bin/false
_apt:x:104:65534::/nonexistent:/bin/false
messagebus:x:105:108::/var/run/dbus:/bin/false
sshd:x:106:65534::/run/sshd:/usr/sbin/nologin
interlock:x:1000:1000::/home/interlock:/bin/bash
lcars:x:1001:1001::/home/lcars:/bin/bash

root@usbarmory:/# cat /etc/shadow
root:*:18068:0:99999:7:::
daemon:*:18068:0:99999:7:::
bin:*:18068:0:99999:7:::
sys:*:18068:0:99999:7:::
sync:*:18068:0:99999:7:::
games:*:18068:0:99999:7:::
man:*:18068:0:99999:7:::
lp:*:18068:0:99999:7:::
mail:*:18068:0:99999:7:::
news:*:18068:0:99999:7:::
uucp:*:18068:0:99999:7:::
proxy:*:18068:0:99999:7:::
www-data:*:18068:0:99999:7:::
backup:*:18068:0:99999:7:::
list:*:18068:0:99999:7:::
irc:*:18068:0:99999:7:::
gnats:*:18068:0:99999:7:::
nobody:*:18068:0:99999:7:::
systemd-timesync:*:18068:0:99999:7:::
systemd-network:*:18068:0:99999:7:::
systemd-resolve:*:18068:0:99999:7:::
systemd-bus-proxy:*:18068:0:99999:7:::
_apt:*:18068:0:99999:7:::
messagebus:*:18068:0:99999:7:::
sshd:*:18068:0:99999:7:::
usbarmory:$6$rcyB4m4EPv$udqWloCZH/Av1IkJVuZHyWMhw/fYkhLGevlo17C3x6qMemSHUmPPAQrvc0SaY.yWVIIU0ADL0g54MZmidcxFn.:18068:0:99999:7:::
lcars:$6$iFljmotV$gnK66oZpz7BD3BqlFpPWoY/Q1tey8in75868neosxypKswjSoNDQotiMBZ9hh.vQBDyltA08z2Vji/QjElv4g.:18072:0:99999:7:::
interlock:!:18072:0:99999:7:::

After adding usbarmory account, running apt upgrade (since image has old kernel) device isn't bootable any more (at least it's not detected by host in which it's plugged in).
Let's try to rebuild image for emmc and flash it.
Well, re‑build fails with patches allready applied errors in linux source, so let's wipe it:
root@813046ba7c77:/opt/armory# rm -Rf linux-* u-boot-2019.07*

root@813046ba7c77:/opt/armory# make all V=mark-two IMX=imx6ull BOOT=eMMC -j 8

pads on board
there is kicad project of production one which just removed pads https://github.com/f‑secure‑foundry/usbarmory/tree/master/hardware/mark‑two 

 	 	 	jtag_mod	jtag_tck	
jtag_ntrst	jtag_tms	jtag_nsrst	jtag_tdo	jtag_tdi	

from changelog those pads might be jtag (since it's enabled in u‑boot), but schematics confirms it.
It seems that 8 gpio pins are available using additional board: https://github.com/inversepath/usbarmory/tree/master/hardware/mark‑two‑debug‑accessory 
sdcard vs emmc speed
root@usbarmory:/mnt/klin/home/dpavlin/usb-armory/usbarmory-debian-base_image# hdparm -Tt /dev/mmcblk[01]

/dev/mmcblk0: # -- sdcard
 Timing cached reads:   664 MB in  2.00 seconds = 331.99 MB/sec
 Timing buffered disk reads:  34 MB in  3.03 seconds =  11.21 MB/sec

/dev/mmcblk1: # -- emmc
 Timing cached reads:   716 MB in  2.00 seconds = 357.40 MB/sec
 Timing buffered disk reads: 128 MB in  3.04 seconds =  42.17 MB/sec

community
https://groups.google.com/forum/#!forum/usbarmory 
https://hackaday.com/2019/09/29/usb‑armory‑mkii‑a‑usb‑c‑thumb‑drive‑based‑linux‑computer‑for‑pentesters/ 
led heartbeat off
https://photos.app.goo.gl/rRrzfbbs4GGjt3ePA 
very bright and annoying in dark room
sbarmory@usbarmory:/sys/class/leds/LED_WHITE$ cat trigger
none kbd-scrolllock kbd-numlock kbd-capslock kbd-kanalock kbd-shiftlock kbd-altgrlock kbd-ctrllock kbd-altlock kbd-shiftllock kbd-shiftrlock kbd-ctrlllock kbd-ctrlrlock mmc0 mmc1 cpu cpu0 [heartbeat]

root@usbarmory:/sys/devices/soc0/leds/leds/LED_WHITE# echo none > trigger

network speed
root@usbarmory:~# iperf3 -c 10.0.0.2
Connecting to host 10.0.0.2, port 5201
[  4] local 10.0.0.1 port 33574 connected to 10.0.0.2 port 5201
[ ID] Interval           Transfer     Bandwidth       Retr  Cwnd
[  4]   0.00-1.03   sec  23.0 MBytes   188 Mbits/sec    0    174 KBytes
[  4]   1.03-2.00   sec  20.6 MBytes   178 Mbits/sec    0    272 KBytes
[  4]   2.00-3.01   sec  21.1 MBytes   176 Mbits/sec    0    286 KBytes
[  4]   3.01-4.01   sec  21.8 MBytes   182 Mbits/sec    0    297 KBytes
[  4]   4.01-5.00   sec  20.1 MBytes   171 Mbits/sec    0    297 KBytes
[  4]   5.00-6.00   sec  21.0 MBytes   176 Mbits/sec    0    329 KBytes
[  4]   6.00-7.00   sec  20.3 MBytes   171 Mbits/sec    0    329 KBytes
[  4]   7.00-8.00   sec  20.4 MBytes   171 Mbits/sec    0    329 KBytes
[  4]   8.00-9.00   sec  20.3 MBytes   171 Mbits/sec    0    329 KBytes
[  4]   9.00-10.00  sec  20.1 MBytes   169 Mbits/sec    0    329 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth       Retr
[  4]   0.00-10.00  sec   209 MBytes   175 Mbits/sec    0             sender
[  4]   0.00-10.00  sec   208 MBytes   174 Mbits/sec                  receiver

iperf Done.

network setup for desktop
dpavlin@nuc:~$ grep usbarmory -A 5 /etc/network/interfaces
# usbarmory
allow-hotplug enx1a5589a26942
iface enx1a5589a26942 inet static
        address 10.0.0.2
        netmask 255.255.255.0
        post-up iptables -t nat -A POSTROUTING -s 10.0.0.0/24 -o eth0 -j MASQUERADE

bluetooth
https://github.com/inversepath/usbarmory/wiki/Bluetooth 
root@usbarmory:/home/usbarmory# microcom -p /dev/ttymxc0

AT+GMR
"1.0.0-017"

armoryctl
usbarmory@usbarmory:~$ sudo apt install armoryctl

since device is on stretch it has go 1.7 which can't compile it.
dpavlin@klin:~/usb-armory$ git clone https://github.com/inversepath/armoryctl

dpavlin@klin:~/usb-armory/armoryctl$ make armoryctl GOARCH=arm
github.com/inversepath/armoryctl/anna_b112
# github.com/inversepath/armoryctl/anna_b112
anna_b112/openocd.go:328:9: undefined: strings.ReplaceAll
anna_b112/openocd.go:329:8: undefined: strings.ReplaceAll
note: module requires Go 1.12make: *** [Makefile:27: armoryctl] Error 2

After compile:
usbarmory@usbarmory:~$ sudo ./armoryctl tusb id
TUSB320
usbarmory@usbarmory:~$ sudo ./armoryctl ble info
manufacturer:"u-blox" model:"ANNA-B1" serial:"0" sw:"1.0.0-017" device_name:"USBARMORY-MKII-DUT-3776"
usbarmory@usbarmory:~$ sudo ./armoryctl se1 info
serial:0x0123455d2a9039e5ee revision:0x00006002
usbarmory@usbarmory:~$ sudo ./armoryctl pmic info
id:0x4("PF1510") family:0xf("15") otp:"A6" rev:0x11

i2c
root@usbarmory:/home/usbarmory# i2cdetect -l
root@usbarmory:/home/usbarmory# modprobe i2c-dev
root@usbarmory:/home/usbarmory# i2cdetect -l
i2c-0   i2c             21a0000.i2c                             I2C adapter
root@usbarmory:/home/usbarmory# i2cdetect -y 0
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- 08 -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- 31 -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- 48 -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: 60 61 -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --