So fast...

Aha! This sound like a bug... Wahroonga Farm? Dairyman?
U mean the RAM? Infomation resides in RAM is gone the moment u turn the machine off (after all, that's why it's called volatile momory). Even if this does happen, upon machine boot up, kernel memory test will flip every bits of the RAM 0->1 and 1->0, nothing of the previous session can survive... So, that's unnecessary.

Be careful when flashing back from OpenWRT to original firmware. You may end up bricking your router if done improperly. Some user in this thread "kena" already.

The following is the right way of flashing back to TP-Link's firmware (Reference):

Step 1
Download the firmware for TL-MR3420 v2 (the filename contains "boot" & the size=4063744 bytes)

Step 2
Cut the first 0x20200 (that is 131,584 = 257*512) bytes from the original firmware

On Linux or MAC, fire up the command prompt, and type:

The dd utility is part of the Linux & MAC OS. For Windows, search "dd for windows", or use HexEdit.

Step 3
Flash the stripped file (size = 3932160 Bytes / 3840 KiB / 3.75 MiB) through web interface.

Quick download -> https://www.box.com/s/kps8yu3wszywuhqzy0c3
This is the firmware without bootloader, uploaded by user on OpenWRT.org (see Post #108).
I've not personally tested it. Use while you can, on your own risk...

This post has been edited by iOnicStorm: Jul 15 2013, 10:03 PM

You can just flash to BlackWidow from Huntsman's web interface.

For those who're interested:
http://wiki.openwrt.org/doc/uci/wireless
See htmode in Common Options under Wifi Devices.

Those steps are just for making your flashable firmware on your own. You can just skip that and terus go to download
https://www.box.com/s/kps8yu3wszywuhqzy0c3 the file and flash using the web interface... Easy?

Yup. That's as easy as that. Have you flash? Or you better do it quick, or your router could possibly go haywire later on... See post #835, and post #839.

Flash back to original firmware first. If it's working alright then wait a few days or a week (use as normal). If it's alright then you can flash to any other firmware as you like later on.

@greenlp_87
Yes. It's a good practice to do a factory reset to restore router to default configuration. Just for safety.

Flash to ROOter (preferably BlackWidow for stability) and use the keep-alive function. Instruction's on the ROOter homepage.

DISCLAIMER: Do it at your own risk! Flashing a new firmware always carries a risk to brick your router. So, make all possible preparation b4 / during / after flash, just to be sure.

This post has been edited by iOnicStorm: Jul 19 2013, 11:16 PM

Could be done successfully with a vanilla OpenWRT. Multiwan should be OK with 2 different ISP, whether backup/fail-over or load balancing.

Last time tried multiwan load balancing on streamyx (ADSL + WiFi) with no success...
Now playing around with macvlan + multiwan...

For reference -> http://wiki.openwrt.org/doc/uci/multiwan
Windows users can try Connectify Dispatch.

This post has been edited by iOnicStorm: Jul 17 2013, 08:23 PM

I think I know the story...

...OpenWRT Good? -> flash OpenWRT -> problems -> flash TP-Link -> brick

Just kidding... Don't take it seriously ya...

This post has been edited by iOnicStorm: Jul 19 2013, 10:57 PM

This requires the use of TTL serial console cable and open the casing to do some soldering...
Not for the faint of heart or of the less adventurous.
Better take it to shop for RMA, or ask someone expert to do it.

BTW, he could've sold it already.

This post has been edited by iOnicStorm: Jul 19 2013, 10:58 PM

Try keywords like "lock", "cell", "lock cell", "mdma" in the bottom left search box.

http://ofmodemsandmen.com/locking.html

This post has been edited by iOnicStorm: Jul 27 2013, 11:53 AM

You meant usb tethering? ROOter can do this.

WDS bridging usually works good only between devices of the same vendor.

MR3420 don't support repeater mode in it's stoke firmware, but other TP-Link devices do:
WA850RE, WA830RE, WA730RE, WA701ND, WA801ND, WA901ND, WR843ND, MR3020 (WISP), etc.

MR3420 can do wireless repeater mode if flashed to OpenWRT (ROOter can do), by creating 2 (virtual) wireless interfaces, 1 in client mode, another in AP mode.

OpenWrt Wireless repeater
http://www.youtube.com/watch?v=3rbsh2zxPnk

DISCLAIMER: Flashing a new firmware always carries a risk to brick your router. So, do that at your own risk! Make all possible preparation b4 / during / after flash!

This post has been edited by iOnicStorm: Jul 27 2013, 11:52 PM

I believe Huntsman did it intentionally to reduce power consumption on initial modem connection stage. That's because most routers don't provide enough current for use on some USB 3G modems, by turning wireless off then all available current can be provided to the USB modem for making the initial connection (I believe mostly all 3G modem will need MAXIMUM power consumption for initiating a connection, and the power consumption will reduce after that according to loads / speed). And recover the WiFi again after the modem has done the connection.

Being a MR3420 V1 user I think you're lucky. There are other firmware to choose from other than TP-Link's and ROOter. Try Gargoyle firmware.

Notes:
- Gargoyle is a heavily moddified OpenWRT but a bit different than the original OpenWRT.
- Use the stable release if possible, rather than the experimental one (possibly with new features unavailable on the stable release, but could be buggy)

This post has been edited by iOnicStorm: Jul 29 2013, 12:01 AM

BTW, ROOter is OpenWRT, a heavily modded OpenWRT.

Beware! Incorrectly flash from OpenWRT back to stock firmware could possibly brick your router.

Sometimes, you cannot just flash the firmware file downloaded off the TP-Link's website. If the filename of the .bin file contains no word of "boot", it's alright. But if it is, then if you flash it from OpenWRT web-interface, you'll end up bricking your router!

Instead, download your firmware file from http://ofmodemsandmen.com/downloads.html
Scroll down to "Factory Firmware" section.

NOTE: TP-Link's firmware file with the word "boot" in it comes with the 128 KiB uboot partition. This is needed to be stripped off before flashing using the OpenWRT web interface. See my previous post (#1375).

Use an USB extension cable and see how it goes.
See post #1357, #1360 and #1417.

This post has been edited by iOnicStorm: Aug 6 2013, 11:31 PM

If you lock band to LTE only, this is what's going to happen.

LTE towers are rare in Malaysia and could possibly be conjested most of the time. If your modem is allowed to "float", when connection cannot be made to the LTE tower due to conjestion, a second tower will be used, and so on. But because user forcing connection ONLY to LTE towers, the modem will always wait for connection to the specific tower, even though there could be other (non-LTE) towers lying around.

Don't use band-locking unless there're many LTE towers in the area, and that their signal is good enough. Just my $0.02.

Could be interference. See post #1549 above.