The sector layout of the ESX2 RTS changed for the release of v3.09r0. The allocation of two additional sectors of flash memory was necessary to support additional RTS features and new babyboard variants. As a consequence, the Type of Hexfile "IEC1131 run-time system" cannot be used anymore for ESX RTS version 3.09r0 and newer. (The RTS for other devices, such as ESX-LT and ESX-Micro is unaffected)
Switch the Type of Hexfile to "User Defined". Change the sectors setting according to the table below, and then flash as normal.
|Size of Flash||Sectors Setting|
|512 kB (standard)||1,2,3,4,5,6|
|1 MB (optional)||1,2,3,4,5,6,17,18|