Is the only difference between the 64 and the 128 the amount of onboard RAM? Is it possible to upgrade a 64 to the same as a 128?
The EP64, especially if you got it from the recent eBay sales in Egypt or Russia, is likely to come with EXOS 2.0 and BASIC 2.0.
EP128s, especially those that were shipped to our friends in Hungary, came with the updated EXOS 2.1 and BASIC 2.1.
If you're not a collector that is trying to keep your Enterprise unopened and in pristine condition, it is highly recommended that you open it up and swap your EXOS 2.0 32KB-ROM for an EXOS 2.4 64KB-EPROM, which has BASIC 2.1 built into it.
That will require soldering one new wire between the EPROM and the Enterprise's motherboard.
While you've got the computer opened up, you can upgrade the Enterprise's RAM, if you wish, although that will need some more soldering, using the existing EXP1 and EXP2 expansion connections that are on your EP64's motherboard.
Since most of the Enterprise's library of software requires a 128K system, that would seem like a good idea.
You can see some photos of my EPROM and RAM installation in the long-running memory expansion thread
here.
I think that I might be the only person with a 512KB memory expansion board available for sale at the moment, and I am in the process of protoyping a new 1MB memory expansion board.
If you don't want to solder things onto your Enterprise motherboard, then you may want to take a look at the Symbiface3 external expansion.
