The 159.devkit image is the latest image available in Intel® Edison Downloads. The 146 image is the latest image that can be installed from the configure_edsion method, this is because the 159 and 159.devkit images are too big for the partitions in 146 so they can be only be flashed manually.
Since you are having issues with the flashall.sh method, then I'd suggest you to flash your board with Flash Tool Lite. You can find the tool and a guide on how to use it in Intel® Edison Downloads.
If you can see the two COM ports but you can’t start a serial connection to the Edison, then it might be related to the board's drivers. Have you installed the board's FTDI driver? In case you haven't, you can find it in D2XX Direct Drivers.
Thanks for your reply. I am reassured that I have the right image and that the configure_edison update failure is to be expected.
With regard to using Flash Tool Lite . I tested and tried many things to no avail. I removed and reinstalled the FTDI driver. Everything checks out apparently but Flash Tool Lite still fails and I am unable to establish a serial link with Putty (even though I am able to open a port).
Anyway, I was able to program the Edison with both the Intel XDK and Eclipse through a wifi connection. That also allowed me to test the UART and it is working, It is all I need so I will stick to this method and not worry about the other issues.