x50v embedded battery issue

[tigerszheng]

coz I wanto use the soft "fring" to make voip call, so I decided to update my X50v from ppc 2003 to wm5, and the terrible start from now.

normal every 2 days x50v will inform there are memory error and I should hard reset it(coz I just use few soft in it, it's easy for me to reinstall it), I hard reset it everytime.

And today it comes again, I hard reset it, found that it's no work any more.

Then I take off the battery, close the battery door, and plug in the usb-chargable cable to laptop, hard reset it, it's work, I can do the initial setting then. the system will report that the embedded backup battery is low.

But when I plug out the cable and put the battery inside, the mem error comes again.

Is it because that the embedded backup battery is dead?

Anyone know how can I select correct battery for x50v(what is the specification for x50v embedded backup battery)?

I have already take out the battery.

Thanks