TP-LINK TL-WR720N v2

Overview
"2050500519", "CA-F120" and "164602002" (11/2016)
 * is silkscreened on the board.

V2 has external fixed antenna (internal Inverted-F in V1).

Links of Interest

 * TP-LINK TL-WR720N on OpenWrt wiki

See also TP-LINK TL-WR720N v3.0 (3G) and v4.0 (CN)
 * (completely different devices under the very same name,
 * see TP-LINK_TL-WR720N v1 page for more info)

Stock firmware
wr720nv2-ru-up.bin bootloader at 0x68d4, kernel at 0x40114
 * (LZMA 6E 00 00 80 00).

FS signature 4x owowowow, BE32 = 1?, BE32 file count, BE32?,
 * 40 char name, BE32 len and ofs (LZMA 5A 00 00 80 00).

Serial Pinouts
[ TX ] ( RX ) ( GND ) ( 3.3V ) You need to solder a jumper wire between TP18 and TP28 on the back
 * of the PCB for TX to work.

TX are logs from router to PC (-> RX on PC side), RX commands back
 * (3.3V to 2.5V resistor divider nearby <- TX).

V1 repair features PCB photos, boot log and unsuccessful flash chip /
 * firmware upgrade to one of MR3220. • same guy? • boot log

Bootloader confusingly indicates only 8 MiB of RAM (pDmaBuf=0x80637910, buffend = 80782514),
 * while VxWorks kernel later allocates full 16 MiB (pDmaBuf=0x80e1c560, buffend = 80f67164).

VxWorks-based WR702N and WR710N exhibit the same bug.

VxWorks
Tap Enter after the boot log to access VxWorks console. help or ? prints commands available.
 * Not very useful since almost everything is hardwired, but provides some insight into inner workings.

Full flash backup
Set up PC for fixed IP 192.168.1.100 with TFTP server, wired connection to LAN port is required.
 * Start terminal at 115200 baud, issue Ctrl+C to stop auto-boot after ~1 s, then

flash read 0 80100000 200000 tftp 192.168.1.100 put full.bin 80100000 200000
 * bootloader and kernel identical to wr720nv2-ru-up.bin without 0x94 bytes header
 * 0x1c0000 - settings (backed up as encrypted config.bin)
 * 0x1e0000 - LAN/Wireless MAC address (6 bytes), 0x1e0010 - WPS PIN (ASCII)
 * 0x1f1000 - calibration area (0x440 bytes), most important part to back up!

Pictures
User Images