Find a photo of identical card that is already upgraded and check if there are any other differences.

Ah, finding exact counterparts of the video cards in question is not easy, at least I never saw ones out there.
But I tried swapping different BIOSes - using ones from 2Mb versions and they still dont see the extra RAM.
Kind of weird, because apart from the empty pads there are no unpopulated placeholders for other elements.

sometimes the cards are laid out for different memory package types, and one or the other is installed, but they're not meant to have both populated.
other times there are also some passive components that need to be populated in addition to the memory.

what card are you talking about in particular?

What card/chip are you trying to upgrade?

Maybe it needs something (i.e. a short between two pads or cutting a jumper) to work with more memory.

Post the photo of your card. Maybe someone has 2MB version in their collection.

This one for example:

Initially it had 4 RAM chips. I bolted on it 1 more meg of RAM, but it does not see it.

might need a different bios, might need other parts populated, hard to tell without manual... I saw some cards with a 3rd resistor network on the top.

mine also only has one bank soldered (SOJ40)

I wouldn't bother with it. It's a low end card and 2MB won't do any good.

Here is a photo of a 2MB configuration with other chips:
https://i.ebayimg.com/images/g/9YcAAOSwZi5eL2oL/s-l1600.jpg

The only diff I can see is one resistor array.
Will try that.
Thanks guys.

As for the quality/perf of the card - it is actually surprisingly good.

I think that R22 may be related to 2mb configuration, but no way to be sure (except you get the schematics). Also there are some other resistors unpopulated that may change card behaviour, and those resistors packs are placed at different places on the "bigger chips" card.

Agreed.
With the lack of schematics i will be taking the non-scientific route - trial and error.
😀