Not really. :)

The latest firmware for the MR3420 V2 supports the E3276.

http://www.tp-link.se/support/download/?model=TL-MR3420&version=V2

http://www.tp-link.se/resources/software/TL-MR3420_V2_130314.zip

TL-MR3420_V2_130314
Published Date 30.05.2013
Language English
File Size 3.77 MB
Operating System Win2000/XP/2003/Vista/7/8/Mac
Modifications and Bug Fixes

Added compatibility for Huawei E3276

Notes Suit for TL-MR3420 v2

Hi,
This is strange, what firmware are you using?

TL-MR3420_V2_121206 works without a problem for me (speed limit excluded) but as soon as I load the TL-MR3420_V2_130314
The router keeps looping with {Identifying, Succesful identification, connecting, disconnected}
Could it be the firmware on the modem?
The router is version 2.2

I´ve got an older version. a TL-MR3420_V1. Will it support the E3276?

E3276 is a LTE 4G modem.
The MR3420 V2 supports 4G modem; while V1 does not. This is announced on TPLINK website.

I am afraid, that I do not know.

In it something is. Thanks for an explanation. All ingenious is simple.

this thread helps http://forum.tp-link.com/showthread.php?74301-Tplink-MR3020-4G-Huawei-E3276-Problem-Resloved.&region=china
It resolved the combine of tp-link with E3276 modem.

Now, the Huawei E3276s-500, E3276s-150, and E3276s-152 are supported by the TP-Link router.