H4 Lot 3908 endlessly showing "Checking Ethernet Connectivity"

[Sir George]

Hi folks,

it's me again, now back with my D3 exchanged to a H4. But.... 
For the record, it's a MVP 86020 LF Rev H4 Lot 3908, Rev. 2.06 (on boot screen) with coaxial SPDIF.
Currently I'm running vomp-dongle-0.3.0-2-Yaris with the correspondig server plugin.

Yesterday, I connected it to my TV an started it, but it looped endlessly trying to boot. Sure thing, I had to increase the version number in vomp-dongle.bin.ver. I did this using the script from http://www.vdr-wiki.de/wiki/index.php/MediaMVP_-_create-dongle-bin-ver
Then it booted fine and ran flawlessly for an hour or so. (btw, I got a complete packaged MVP with new remote in turn of my broken D3  - nice of Hauppauge [after keeping me waiting for 2 and a half months...]

Well, but obviously I was too confident... I wanted to test how fast the MVP would boot from flash and selected reboot...
The first time it still got as far as "Loading Application" (afair), but the next time I got stuck with "Checking Ethernet Connectivity", getting no link on MVP and switchport.
When I disconnect it long enough (hours?) from mains, it still sometimes gets up to "Loading Application", but after a few minutes, the screen goes black and it falls back to "Checking Ethernet Connectivity"....
I even tried with another switch (in fact in place of my currently working D3A), but with no success.

What the heck happened here? Was the flash written badly somehow? And I have no idea how to reset the box (besides soldering a serial port and intercepting the boot, OK...  but I'm not so brave when it comes to soldering on SMD-boards...)

Update:
I just powered it up again (after some hours) and managed to get to "Contacting servers...". My vompserver.log said the following:

Code Select Expand

20:12:56.693986 [debug]  MVPRelay - MVPRelay request from 10.0.0.12
20:12:56.694186 [debug]  MVPRelay - Sending my IP as a000003
20:13:01.423193 [debug]  Client - Received chan=3 kats=1225912381
20:13:01.438942 [debug]  Client - Waiting
20:13:01.755435 [debug]  MVPRelay - MVPRelay request from 10.0.0.12
20:13:01.755601 [debug]  MVPRelay - Sending my IP as a000003
20:13:02.003847 [debug]  MVPRelay - MVPRelay request from 10.0.0.12
20:13:02.004015 [debug]  MVPRelay - Sending my IP as a000003
20:13:03.513926 [debug]  Tftpd - Wait finished
20:13:03.514072 [debug]  TftpClient - Client handler started
20:13:03.514215 [debug]  Tftpd - Starting wait
20:13:03.514317 [debug]  TftpClient - RRQ received for dongle.bin.ver
20:13:03.514397 [info]   TftpClient - File: '/usr/share/vdr-plugin-vompserver/dongle.bin.ver'
20:13:03.514482 [info]   TftpClient - threadMethod terminating connection
20:13:07.459839 [debug]  Client - Received chan=3 kats=1225912387
20:13:07.475584 [debug]  Client - Waiting
20:13:13.387336 [debug]  Client - Received chan=3 kats=1225912393
20:13:13.406987 [debug]  Client - Waiting
20:13:13.505800 [debug]  Tftpd - Wait finished
20:13:13.505967 [debug]  TftpClient - Client handler started
20:13:13.506407 [debug]  Tftpd - Starting wait
20:13:13.506528 [debug]  TftpClient - RRQ received for dongle.bin.ver
20:13:13.506630 [info]   TftpClient - File: '/usr/share/vdr-plugin-vompserver/dongle.bin.ver'
20:13:13.506713 [info]   TftpClient - threadMethod terminating connection
20:13:18.505742 [debug]  Tftpd - Wait finished
20:13:18.505921 [debug]  TftpClient - Client handler started
20:13:18.506170 [debug]  Tftpd - Starting wait
20:13:18.506280 [debug]  TftpClient - RRQ received for dongle.bin.ver
20:13:18.506419 [info]   TftpClient - File: '/usr/share/vdr-plugin-vompserver/dongle.bin.ver'
20:13:18.506514 [info]   TftpClient - threadMethod terminating connection

(The "Client - Received" messages originate from my second mvp)
I tried to update ther vom-dongle.bin.ver, but didn't manage in time. And the box hung again...
After a power reset I get the same result as above (as the subjet says...)