Repeat Post :
OK, I have tested my new MR3020 modem on the E367 (firmware flashed 8ta version) and E372 (firmware flashed K4605).
It seems to work well on both of those, which immediately makes it much better than the MR3420, as this modem does not properly support either of those.
But I haven't tested the range of the MR3020, this might be lacking, will report back.
The MR3420 should get an urgent firmware upgrade, or be recalled if the problems are a hardware issue.
Actually, I may use the MR3020 as a 3G router, and the MR3420 as an Access Point, that should solve all the problems.
I have absolutely no problems using either the E367 or E372/K4605 with the MR3420.