I have just spent the afternoon loading the manufacturing image into a connectme9210 and then, starting from this basis, loading images from V126.96.36.199 and back adn forth form V188.8.131.52 to V184.108.40.206. After seeing your massage, I got my module back to the V220.127.116.11 image and rom.bin and tried loading a 7.4.2 image.bin.
The problem I am having is that I can't get any of these configurations to fail.
Now, I am NOT suggesting that you are not running into a problem. On the contrary, I am trying to understand what is going on in a effort to get it fixed.
When your modules come up for the first time (assuming you have access to the serial dialog) what version is displayed at the top? I need the exact version including all digits and periods contained therein.
When you then load your V7.4 image, what version is displayed at the top. Again I need the exact nomenclature.
What process do you use to "program" the modules? ftp from the command line, ftp from a GUI (such as filezilla) please specify, netosprog, some other method. Please be as exact as possible.
Also what are you loading into the module? image.bin (the application), rom.bin (the bootloader) or both?