If you have soldering skills you need this http://es.aliexpress.com/item/6Pin-USB-2-0-to-TTL-UART-Module-Serial-Converter-CP2102-STC-Replace-Ft232-Includes-a/32609844312.html?spm=2114.43010308.4.18.kx7WsV
And download the drivers from here http://www.silabs.com/products/mcu/Pages/USBtoUARTBridgeVCPDrivers.aspx#windows
And you need to see the 2 parts of this video
Part 1 http://youtu.be/t35Pei_eb6o
Part 2 http://youtu.be/wCwBvoueBG4
I don't care what you flashed on them, but if you post the truth, it will be easier to help you
e.g. if you converted to UBNT and some went wrong the programmer has a recovery mode for bad flash
If you went OpenWrt you have Failsafe mode
Etc. etc.

Like I said, there has been no non TP-Link firmware on this unit. I was attempting to flash from 4.4.4 to 4.4.8

I do have a usb serial converter, and have already soldered in the pins / connected. 8N1 32800

This is the output from the serial terminal:



AR2315 rev 0x00000086 startup...
sysConsoleDump: type 0x00000380
epc: 0x2e77330a bva: 0x2e77330a sr: 0x10400002 cse: 0x10800010
R0: r0: 0x00000000 at: 0x00000001 v0: 0x00000000 v1: 0x0000798c
R4: a0: 0xa0480ae4 a1: 0x80592580 a2: 0xffffffff a3: 0x8059254a
R8: t0: 0x8059b36c t1: 0x00000006 t2: 0x80592544 t3: 0x80591a58
R12: t4: 0x00000000 t5: 0x00000004 t6: 0x00000014 t7: 0x0000000a
R16: s0: 0x0000001f s1: 0x9fd14d38 s2: 0x77772e77 s3: 0x330a7777
R20: s4: 0x2e77330a s5: 0x77772e77 s6: 0x330a7777 s7: 0x2e77330a
R24: t8: 0x00000077 t9: 0x2e77330a k0: 0x00000000 k1: 0x00000000
R28: gp: 0x80598990 sp: 0x8047fea0 fp: 0x77772e77 ra: 0x2e77330a


It repeats over and over... Like in the video I have tried to enter "tpl " over and over again, but still wont stop repeating. Does that suggest this is beyond saving???

you should type "tpl" in a notepad and copy "tpl" and Paste with right click in the window...

regards...

Sorry I typed incorrectly. 34800 baud 8N1

I have tried to copy tpl and right click to *paste* it into putty in order to stop the cycle. No luck. :(

you check the conection betwhen usb/serial converter and serial port of 5210 is correct????
converter Rx-------------Tx serial 5210
converter Tx-------------Rx serial 5210
converter GND----------GND serial 5210
use this pic for guide




when the secuence " Autobooting in 1 seconds" appear, paste the " tpl" command, prompt with " ar7240>[SIZE=2]"[/SIZE] must be show...



Regads...

Toyotahead, I am also having exact same output when I tried upgrading firmware...no ubiquity/openwrt/dd-wrt just tp-link

now the device just boots again and again..Serial console dumps output too similar to yours.
Strange why this happened .

[CODE]AR2315 rev 0x00000086 startup...

panic: romStart failed!
sysConsoleDump: type 0x10400000
epc: 0xfffeefbf bva: 0x137aad2a sr: 0x10400000 cse: 0xb080007c
R0: r0: 0x00000000 at: 0xbfc00000 v0: 0xffffffff v1: 0x805916e0
R4: a0: 0xbfc00a07 a1: 0xb1100000 a2: 0x00000000 a3: 0x80594eff
R8: t0: 0x00000040 t1: 0x00000020 t2: 0x80594ef7 t3: 0x805916f8
R12: t4: 0x00000000 t5: 0x0000000d t6: 0x47e3a63c t7: 0x4c75a632
R16: s0: 0x00000002 s1: 0xbf9e5b5f s2: 0xffd3ffd8 s3: 0xfffaf346
R20: s4: 0xf3aafd8f s5: 0xb3efbd59 s6: 0xd774ddcf s7: 0xdfff31df
R24: t8: 0x00000001 t9: 0x805916d8 k0: 0x00000000 k1: 0x00000000
R28: gp: 0x80598630 sp: 0x8047fff0 fp: 0x5fffaf49 ra: 0xbfc00a28[/CODE]

were you able to salvage your CPE or have to buy another one.. Can you please suggest something.
I am getting feel that spi programmer would be required to mend the bootloader..