Keithley 2400 Error 601 and couple of questions

[analogRF]

We have a Keithley 2400 here in our university lab that  briefly shows Error 601 at startup
The lithium battery is dead (0.2V) and it is soldered to the board but I will replace it. However I have two questions:

1-are the calibration constants lost and the unit definitely needs calibration now?
I am confused by the service manial because somewhere on page 4-8 it says:"...The RAM is battery backed-up, providing
continued storage of data buffer information during power-down cycles. All calibration
constants and system setups are stored in a separate serial EEPROM."
but then on page 4-12 it says:"...Calibration constants and user-defined parameters will be lost when the battery is
replaced. The Model 2400 must be re-calibrated..."

so which one is it? Are they in EEPROM or NVRAM?

2-The best DMM I have available is a new DMM6500. Can I do the calibration using this DMM or I definitely need a 3458A?

thanks for your help

[msimunic]

I have same question. 

[TheSteve]

If the battery is already dead there is really no need to worry, if anything is going to be lost, it is already lost. In the case of the 2400 the cal data should be an eeprom anyway. It is just clock and user config/data and held in ram.