mergehex does work with file paths with "..\" in them. Here's my folder structure:
project root
Firmware
Application
Bootloader
SDK_Libraries
nRF5_SDK_17_0_2
I'm trying to use mergehex to merge the bootloader, application S132 softdevice, and bootloader settings page into 1 hex file to production programming. The path to the softdevice has a few "..\" in the path, and merghex does not work with it. Here's the path to the softdevice that causes mergehex to fail with error "an invalid argument was provided"
C:\Projects\tempProject\BLE\Firmware\Application\..\..\SDK_Libraries\nRF5_SDK_17_0_2\components\softdevice\s132\hex\s132_nrf52_7.2.0_softdevice.hex
I'm using a project variable in the build process that results in that "..\..\" in the middle of the path string. I can't hard code the full path to the softdevice because other developers (and the build server) store the project files in different locations.