Firmware

General_SD-4c5e8e2e.bin

ASM firmware. May work with 3 devices, including SD-6C80E-GN, SD-6C82E-GN, SD22204T-GN.

Download

Permanent copy on the Internet Archive (item page)

Hardware IDs this firmware's installer accepts (3 devices).

Where these IDs come from

Install: the installer's device list (board families), 5 IDs, vendor General (not counted: a more specific list exists)
check.img: the device's own hardware check list, 3 IDs

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

Flash layout: 15 partitions, 9 written by this firmware

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

Partition	Start	End	Size	Image	Filesystem	Built
MinBoot	0x0	0x40000	256.0 KB	dhboot-min.bin.img	—	2016-05-17
U-Boot	0x80000	0xc0000	256.0 KB	dhboot.bin.img	—	2016-05-17
hwid	0xc0000	0xe0000	128.0 KB	not written	—	—
partition(ro)	0xe0000	0xf0000	64.0 KB	partition-x.cramfs.img	cramfs	2016-05-17
Kernel	0xf0000	0x270000	1.5 MB	kernel.img	—	2016-05-17
romfs(ro)	0x270000	0x3c0000	1.3 MB	romfs-x.squashfs.img	squashfs	2017-03-07
web(ro)	0x3c0000	0x5d0000	2.1 MB	web-x.squashfs.img	squashfs	2016-05-17
user(ro)	0x5d0000	0xe00000	8.2 MB	user-x.squashfs.img	squashfs	2017-03-07
updateflag	0xe00000	0xe30000	192.0 KB	not written	—	—
config	0xe30000	0xea0000	448.0 KB	not written	jffs2	—
product(ro)	0xea0000	0xeb0000	64.0 KB	pd-x.squashfs.img	squashfs	2016-05-17
custom(ro)	0xeb0000	0xed0000	128.0 KB	custom-x.squashfs.img	squashfs	2016-05-17
backupker(ro)	0xed0000	0xfb0000	896.0 KB	not written	squashfs	—
backupfs(ro)	0xfb0000	0x1000000	320.0 KB	not written	squashfs	—
user1	0x1000000	0x2000000	16.0 MB	not written	jffs2	—

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