check.img from LOREX_IPC-HFW1XXX-Alps_Eng_NP_V2.420.LR00.3.R.20160105.bin has:
pozzello@sfo-lp82w:~$ strings check.img.lorex
strings: 'check.img.lorex': No such file
pozzello@sfo-lp82w:~$ strings check.img.lorex
check
"DefaultLanguage" : "English",
"DefaultVideoStandard" : "NTSC",
"SupportLanguages" : "English",
"hwid" : [
"IPC-HDW1020S-V2:01:02:05:49:1C:00:01:00:00:00:00:190:00:00:00:00:00:00:00:00:40",
"IPC-HFW1025B-V2:01:02:05:49:1C:00:01:00:00:00:00:190:00:00:00:00:00:00:00:00:40",
"IPC-HDW1120S-V2:01:02:05:38:1C:00:01:00:00:00:00:190:00:00:00:00:00:00:00:00:40",
"IPC-HDW1220S-V2:01:02:05:3D:1C:00:01:00:00:00:00:190:00:00:00:00:00:00:00:00:80",
"IPC-HDW1220S-V2:01:02:06:1F:1C:00:01:00:00:00:00:190:00:00:00:00:00:00:00:00:40",
"IPC-HFW1225B-V2:01:02:05:1F:1C:00:01:00:00:00:00:190:00:00:00:00:00:00:00:00:40",
"IPC-HDW1320S-V2:01:02:05:1F:1C:00:01:00:00:00:00:190:00:00:00:00:00:00:00:00:80",
"IPC-HDBW1325R-V2:01:02:05:1F:1C:00:01:00:00:00:00:258:00:00:00:00:00:00:00:00:80"
]
while the one from that Dahua FW has:
pozzello@sfo-lp82w:~$ strings check.img
check
"DefaultLanguage" : "English",
"DefaultVideoStandard" : "PAL",
"SupportLanguages" : "English",
"hwid" : [
"IPC-HFW1220B-V2:01:02:02:4F:1C:00:01:00:00:00:00:258:00:00:00:00:00:00:00:00:80",
"IPC-HFW1220S-V2:01:02:02:4F:1C:00:01:00:00:00:00:258:00:00:00:00:00:00:00:00:80",
"IPC-HDBW1220R-V2:01:02:05:55:1C:00:01:00:00:00:00:258:00:00:00:00:00:01:00:00:80",
"IPC-HFW1220M-V2:01:02:02:58:1C:00:01:00:00:00:00:258:00:00:00:00:00:00:00:00:80",
"IPC-HDBW1220R-S-V2:01:02:05:58:1C:00:01:00:00:00:04:258:00:00:00:00:00:00:00:00:80",
"IPC-HDBW1220R-S2:01:02:05:65:1C:00:01:00:00:00:00:258:00:00:00:00:00:00:00:00:80",
"IPC-HDBW1220R-S-S2:01:02:05:65:1C:00:01:00:00:00:04:258:00:00:00:00:00:00:00:00:80",
"IPC-HFW1220M-AS-S2:01:02:02:51:1C:00:01:0E:01:01:04:258:08:03:00:00:00:00:00:00:80",
"IPC-HFW1220M-S-S2:01:02:02:51:1C:00:01:00:00:00:04:258:00:03:00:00:00:00:00:00:80",
"IPC-HDW1320S-V2:01:02:05:1F:1C:00:01:00:00:00:00:190:00:00:00:00:00:00:00:00:80",
"IPC-HDBW1325R-S-V2:01:02:05:1F:1C:00:01:00:00:00:04:258:00:00:00:00:00:00:00:00:80",
"IPC-HDBW1325R-V2:01:02:05:1F:1C:00:01:00:00:00:00:258:00:00:00:00:00:00:00:00:80",
"IPC-HDBW1320R-S-V2:01:02:05:61:1C:00:01:00:00:00:04:258:00:00:00:00:00:00:00:00:80",
"IPC-HDBW1320R-V2:01:02:05:61:1C:00:01:00:00:00:00:258:00:00:00:00:00:00:00:00:80",
"IPC-HFW1320M-AS:01:02:02:19:1C:00:01:0E:01:01:04:258:08:00:00:00:00:01:00:00:80"
]
while IPC-HDW1320S-V2 is listed in both, are you sure that matches the HWID of your Lorex/Flir ?
what does URL "http://<cam-ip>/cgi-bin/magicBox.cgi?action=getSystemInfo" return in any browser?
Also, the Dahua FW defaults to PAL, while the Lorex/Flir defaults to NTSC, which may be related to the resolution settings. If there's a GUI setting for NTSC/PAL (typically in the 'image' config page, try toggling that and see if the behavior remains...