Firmware

DH_IPC-HX8X4X-Nova2_Eng_P_Stream3_V2.622.0000.2.R.20171209.bin

Dahua firmware released Dec 9, 2017. May work with 12 devices, including IPC-HF81249F-FR, IPC-HF8242FP-FD, IPC-HF8242FP-FR.

Download

Permanent copy on the Internet Archive (item page)

Hardware IDs this firmware's installer accepts (12 devices).

Where these IDs come from

hwid: the device's own hardware check list, 12 IDs
Install: the installer's device list (board families), 1 ID, vendor General (not counted: a more specific list exists)
check.img: the device's own hardware check list, 12 IDs

Read from inside the firmware (dahua package (zip variant)).

Flash layout: 16 partitions, 7 written by this firmware

From the firmware's partition table (partitionV2.txt).

Partition	Start	End	Size	Image	Filesystem	Built
U-Boot	0x200000	0x300000	1.0 MB	dhboot.bin.img	—	2017-12-09
hwid	0x300000	0x400000	1.0 MB	not written	—	—
updateflag	0x400000	0x500000	1.0 MB	not written	—	—
partition(ro)	0x500000	0x600000	1.0 MB	partition-x.cramfs.img	cramfs	2017-12-09
Kernel	0x600000	0x1000000	10.0 MB	kernel.img	—	2017-12-09
romfs(ro)	0x1000000	0x9000000	128.0 MB	romfs-x.squashfs.img	squashfs	2017-12-09
custom(ro)	0x9000000	0x9800000	8.0 MB	custom-x.squashfs.img	squashfs	2017-12-09
product(ro)	0x9800000	0xa000000	8.0 MB	pd-x.squashfs.img	squashfs	2017-12-09
web(ro)	0xa000000	0xe000000	64.0 MB	web-x.squashfs.img	squashfs	2017-12-09
lens	0x1bb00000	0x1c000000	5.0 MB	not written	—	—
ext	0x1c000000	0x30000000	320.0 MB	not written	—	—
firmware(ro)	0x30000000	0x70000000	1.0 GB	not written	ext4	—
syslog	0x70000000	0x71000000	16.0 MB	not written	ext4	—
config	0x71000000	0x72000000	16.0 MB	not written	ext4	—
backup	0x72000000	0x73000000	16.0 MB	not written	ext4	—
appdata	0x73000000	0xf3000000	2.0 GB	not written	ext4	—

Other files for much of the same hardware, from any vendor.