It took a couple attempts and some digging in these forums to figure it out, but I have now successfully upgraded my ReadyNAS Pro 2 from 1GB to 2GB of memory. The key was to use a SODIMM with 8 memory chips. None of the SODIMMS I tried with 16 chips would work. What I have in there now is a Crucial CT25664BC1339. Ran memory test for several hours with no issues. Now that I have the additional memory, my full backups no longer hang. Well worth the $12 upgrade.
That ram upgrade still working ok for you? No side effects?
I have the same nas as you, and the opportunity to get the same ram, but I'm a little fearful of possible corruption later on. Especially since I read mdgm's post here: viewtopic.php?f=110&t=61221#p343265
If it doesn't work properly but passes the memory test you could get data corruption.
