Tony Verhulst wrote:

.... The reason for the batteries is to ensure integrity of the data
stored in NVRAM, so the security info will be lost when it loses all
power.


This is off track but the whole point of NVRAM (*Non* *Volatile* Random
Access Memory) is that data will NOT be lost when you remove power.

Tony V.

Hi Tony, I can't explain why, but take my word for it, you will have to send the
unit to the factory if it loses backup power for a moment. I'm not sure whether
the security code is in volatile memory or not, but even a momentary power loss
means the unit reports "invalid secret key" and refuses to work. No negotiation,
even though the contents of the NVRAM remain.

Conversely you can run it till the battery is discharged to the point it will
not boot, and there is no problem.

So - if you do decide to open the little flap and replace the battery, be sure
to maintain power somehow.