Check
this Excel spreadsheet and see if your model number is listed. If so, you MIGHT be able to use one of the firmware
downloads from that site. This MIGHT comes with the usual warnings: if it bricks, it's your fault for wanting to upgrade. The more sane/safer logic is, if it works well enough, leave it alone.
ftp://ftp.asm.cz/Dahua/kamerove_systemy/_Firmware/04IPC/IPC-HX5(4)XXX-Adreia/General/20151106/General_IPC-HX5(4)XXX-Adreia_Eng_P_Stream3_V2.420.0009.0.R.20151106.bin
The
firmware release notes seem to indicate that two months later in November 2015, the following changes were distributed:
1. Fix the bug that NVR cannot get alarm configuration from IPC.
2. Fix NTP synchronization inaccurate problem.
3. Support Onvif 2.4.1.
4. Close telnet port.