Version: <=1.12 but also applicable to other older versions
The APS in question was running on v1.12 and needed to be upgraded to v2.60 and any firmware updates would continually fail (even other intermediate versions). The below procedure is not specific to this update and can also be used for updating from other older versions.
Install the 2.60 release on the Server PC and connect the PC to the APS directly (no network router or switch in-between).
Make sure nothing else is connected to the APS. Make sure the Dicentis services on the server PC are stopped.
When downloading the firmware to the APS it will fail the first time because of the change in name on the APS between version 1.12 and 2.60. Download the firmware again and then it will be fine.
If the update fails a second time, please check the LED behaviour of the APS:
Front LED should show alternating Green/Amber.
If not; switch the APS off and on again and re-try the update.
If the update keeps failing, the problem could also be caused by the PC used in the updating process, try a different PC and connecting cabling and follow the above steps once more.