Question about RAM upgrade

[Kyocera]

After checking out the Access IBM tutorial for my t42 I have to defer to my quote at the bottom "I'm not acting confused, I am confused". There is a little door next to the battery when removed has a memory slot, and from other stuff I have read there are two slots under the keypad. I have 512 installed from the factory and ordered another 256 (on sale). What's the deal with the little cover next to the battery if you install the upgrade under the keypad?

[mysbca]

There is only 1 memory slot under the keyboard. You add your upgrade to the bottom slot next to the battery.

T42 Hardware Maintenance Manual:
ftp://ftp.software.ibm.com/pc/pccbbs/mo ... 9t6192.pdf

[Kyocera]

Thanks for the manual!