VW up! maps and more NAVIGON 7.10.25 CB1100 update error because of low memory

Today I tried to update my VW up! maps + more System to Software Version 7.10.25. Navigon Fresh told me, there's not enough space free in the built-in memory to make the update (Error CB1100). Here's how the error looks like:

The issue is also discussed in the upownersclub:
http://www.upownersclub.co.uk/forum/navigon-software-update-710_topic2759_page2.html
and german the up-szene.de
http://www.up-szene.de/forum/viewthread.php?thread_id=457.
and the danish VAGcars.dk
http://www.vagcars.dk/phpbb/viewtopic.php?f=2&t=54243&start=2820
and the german motor-talk.de
http://www.motor-talk.de/forum/maps-more-update-dezember-2012-probleme-t4350892.html
and in the netherlands
http://www.vwupforum.nl/viewtopic.php?f=8&t=1508&p=25167&hilit=update#p25167
and in upsociety.de
http://www.upsociety.de/index.php?page=Thread&threadID=149&s=bea86988b2710f377153f9496e9560edf7a09a31
and briskoda.net
http://www.briskoda.net/forums/topic/261824-move-fun-pid-update-71025-problemsolved/

Looking through the boards, the problem also seems to affect the Skoda Citigo Move & Fun. I did not find entries that it's also affecting the SEAT Portable so far, but since it's the same hardware it may be.

How-I-fixed-It:
There's no real "fix" for this so far, just a workaround using an USB-Stick as temporary memory (Thanks to user nightbow in the upownersclub):
- You need an empty usb stick with 4GB or more.
- Copy all data from the navi on the stick.
- Deduct the navi from usb.
- Start the program navigon fresh and start the update!
- Software is updated on the USB stick now
- Finish navigon fresh
- Then naviagate on the usb stick to the folder NAVIGON map and delete some of the maps you don't need
- Connect the navi again and delete everything on it
- Copy all data from the stick on the navi andconnect it to the car

German / Deutsch (Danke an user CitiGo) im up-szene.de Forum:
- Die kompletten Daten vom internen Speicher auf den USB-Stick kopieren.
- M&M vom PC trennen.
- Navigon Fresh starten
- Der USB-Stick sollte jetzt als M&M erkannt werden
- Update starten
- Achtung: der Stick wird nach fertigstellung nicht mehr von Navigon Fresh erkannt
- Nach fertigstellung des Updates Navigon Fresh wieder beenden.
- Nicht benötigte Karten (xxxx.map) vom USB-Stick löschen. (NAVIGON->map)
- M&M wieder mit dem PC verbinden und den gesamten internen Speicher löschen.
- Den kompletten Inhalt des USB-Stick auf das M&M kopieren
- M&M vom PC trennen -> das M&M sollte jetz neu booten
- M&M mit dem Auto verbinden

Here's a little update this:
- Navigon Support told me to buy a 4 GB SD-Card to increase the device memory. But they were not able to tell me so far, whether the card has to stay always in the slot or not. So I'll not gonna buy anything before this is clear.
- User telephoneman in the motor-talk.de-Forum wrote, he got told by the Navigon Support to send it to them to get it replaced. According to Navigon this is a known issue!
Anyway.
- Today i contacted VW support directly on their free german support number 0800-8655792436 and a very friendly woman told me she'll forward my request to the responsible people inside VW. She told me they'll get back to me within a day or two.

Here's the next update:
- The Lady called me back and said, since it's a third-party product, I have to get this sorted out with Navigon directly. I should also see my local VW dealer to see, if they can help me there.

I got a new mail from the Navigon Support:
- If i use a SD-Card with no more than 4GB, than the device will store some of the data on this card. The Card then has to be ALWAYS in the device for it to work and they do not recommend storing Music on the Card
(In my words: If I do it like this, I will not be able to Play Music from th e SD Card any more.)
In the end they told me to talk to my VW dealer since he's responsible to handle this issue from their Point of view.

Latest update:
My VW dealer ordered a new Maps&More device for me. The new one does not show the issue.