Looking into the usb port problem, after taking the N900 apart it is very clear to see that because of bad design the usb port fixing on the m/b is so bad a design fault on the N900 it is destined to break off, this means only a re-design will put it right.
A temp repair is possible but will invalidate warranty if not done by Nokia so it appears.
Where does that leave us ? after looking at the thread regarding the usb problem it seems many people are having problems with Nokia regarding this.

I have 2 N900s, one of them had the micro usb just fall out, nokia replaced it with a new one. Treat it with care and Nokia are willing to replace it if this happens.

It appears that you can reflash without using the USB port and you can certainly recharge without using the USB port. It appears to me, then, that the USB port is not essential -- please correct me if I'm wrong. Also, the last poll I saw gave a big majority to users who were NOT having problems with their USB ports. I'm not having problems with mine, for example.

So I see no reason for alarm.

Can you please explain how is possible to flash without the usb port.

I've just been told that Nokia won't repair my phone due to "evidence of user damage", it is very much a grave concern.

That poll was created a while ago, and I initially voted no issues, but now I obviously need to change my vote (not allowed)

Great, and I see someone thanked you for this comment.

I don't suppose you noticed that I used weasel words like "appears" and "Please correct me if I am wrong."?

I suppose those words indicated to you and the person who thanked you that I was absolutely sure that you could flash without the usb port and could come up with exact instructions.

However, if you go to the Wiki and look in the Overclocking sections, you will see an area with the following headings:

"6 Changing the Kernel
6.1 Installing a modified Kernel
6.1.1 Flashing using PC
6.1.2 Flashing from N900 xterminal"

Note 6.1.2 indicates that you can do some flashing from the N900. In fact, I have done it myself. Perhaps that has more limits than I realize, but that is why I made the statement in question.