There is some weirdness in the upgrade process, so maybe Agilent is fixing the installer. You may want to wait for them to repost it. If you want it now pm me, the installer is 26MB.
If you already have the serial port driver installed, its fine, but the upgrade installer does not install the driver, and appears to hangs if it can't find it, nor gives you a message it can't find it or its not installed.
Once the serial port driver is properly installed the upgrade software finds the DMM in a snap. The .net framework based software is slow, is > 10 minutes for the PC side on Win7, but once OK its very fast for the firmware upgrade to the DMM, even with the default baud rate. The install software or the driver have no bugs, otherwise.
The meter works more reliably but there are residual issues, none of them are critical, that remain unchanged. For example, The artifact 1kVAC appears by manipulating the switch with 15VDC being measured, then slowly disappears. Other minor issues that exists in this model aren't in the 1252a or the 87V.
That file just contains the firmware itself (U1272A_V200_0525.AG), not the updater software. There's supposed to be an .exe file with the program that actually loads the firmware that I can't get.