It is probably some China-specific model, right?
Checking from Netgear's site it looks like it has a separate firmware ID:
http://kb.netgear.com/app/answers/detai … -%28gpl%29
WNDR3800
For Firmware Version 1.0.0.16, 1.0.0.18, 1.0.0.24, 1.0.0.32, 1.0.0.34, 1.0.0.38, 1.0.0.38, 1.0.0.40, 1.0.0.44, 1.0.0.48
WNDR3800-1CHNAS
For Firmware Version 1.0.0.51CH
WNDR3800-1SWNAS
For Firmware Version 1.0.0.8
Most likely it has a different firmware ID and to successfully flash another firmware to it, the other firmware should first be modfied to contain the required ID string. Then the OEM TFTPmode or upgrade will accept the new firmware as genuine/compatible.
3700v1 used to have similar North America version and Openwrt contains mod for that ( the -NA version). Probably someone should analyse that CH version original firmware and define the needed patch.
EDIT:
The difference gets embedded to the firmware file's header info. See example regarding WNDR3700v1. Region code NA has been set in the firmware.
Normal WNDR3700v1 factory.img:
00000000 64 65 76 69 63 65 3a 57 4e 44 52 33 37 30 30 0a 76 device:WNDR3700 v
00000011 65 72 73 69 6f 6e 3a 56 4f 70 65 6e 57 72 74 2e 72 ersion:VOpenWrt.r
00000022 33 39 37 38 39 0a 72 65 67 69 6f 6e 3a 0a 00 00 00 39789 region:
00000033 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000044 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000055 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000066 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000077 00 00 00 00 00 00 00 00 00 33 37 30 30 93 ec 7b 06 3700“ì{
North America version:
00000000 64 65 76 69 63 65 3a 57 4e 44 52 33 37 30 30 0a 76 device:WNDR3700 v
00000011 65 72 73 69 6f 6e 3a 56 4f 70 65 6e 57 72 74 2e 72 ersion:VOpenWrt.r
00000022 33 39 37 38 39 0a 72 65 67 69 6f 6e 3a 4e 41 0a 00 39789 region:NA
00000033 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000044 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000055 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000066 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000077 00 00 00 00 00 00 00 00 00 33 37 30 30 93 ec 7b 06 3700“ì{
If you want to experiment, check with a hew editor the first bytes of the original China version. Is there a CH region code? If yes, then you might try hex editing the Openwrt firmware file to contain the same CH: "43 48 0a" (?) instead of the default "0a 00 00".
(Last edited by hnyman on 8 Mar 2014, 09:41)