HT-D5300 Downgrade firmware from 1014

[pandorumdude]

Hi guys,

Can't seem to find the answer on the forums. I have HT-D5300 3d Blu Ray HOme Theatre setup. I've recenlty updated to 1014 firmware version and am having this Cinavia issue. I think i've loacted older versions of the firmware online being B-FIRHTSWWC 1009.1 and B-FIRHTSWWC 1010.0

But I dont know how to install them. I've installed one copy of one of the firmwares on a USB thumbdrive. Gone into the software upgrade menu and chosen to update firmware via USB but the error is "no file available to upgrade"

Can someone please help. I've also just realised my other samsung Home Theatre system HT-D6750w has also been upgraded to 1014 version so i'm expecting i'll have the same Cinavia issues there.

Thanks

[smilemp13]

Hello,

To find the version you should open info.txt. Please let us know the version you have. In case you have an older version (1009, 1010 or 1012 versions without cinavia) we can start to figure out on how to downgrade.
On major_version and minor_version should be 1015 (or bigger number than 1014 to make upgrade), validinfo.txt containing a key in HEX with 8 digits for each type of files exe.img, Image, rootfs.img.
Corresponding files with extension .vs and cs (length key 256/HEX) should match with the key is located at the end of each file; exe.img.sec, rootfs.img.sec and Image.sec. Anyway, please upload the files on 4shared/rapidshare whatever sharing service you know and post the link here.

Thanks

[pandorumdude]

These were the links I obtained the firmware (which I hope is the correct version)

http://drivers.softpedia.com/get/DVD-Bl ... 0091.shtml

http://www.samsung.com/us/support/owner ... T-D5300/ZA under the firmware section 1010.0

[arris69]

Hello,
...
Corresponding files with extension .vs and cs (length key 256/HEX) should match with the key is located at the end of each file; exe.img.sec, rootfs.img.sec and Image.sec.
....

at the end of the .sec files are no keys, this are signatures (sha1 digest) of the decrypted image.
.vs is the encrypted sha1sum of the firmware version
.cs is the encrypted sha1sum of the decrypted image file (yes i know, samsung devs has some kind of paranoia but no plan about real security)

[smilemp13]

Please change the name from ?HT-D5300 Downgrade firmware from 1014? into ?HT-D5300 Downgrade firmware from 1010/SWWC? since that this is your actual version (US), in EU is 1014.

[Shhhh]

Hello,
...
Corresponding files with extension .vs and cs (length key 256/HEX) should match with the key is located at the end of each file; exe.img.sec, rootfs.img.sec and Image.sec.
....

at the end of the .sec files are no keys, this are signatures (sha1 digest) of the decrypted image.
.vs is the encrypted sha1sum of the firmware version
.cs is the encrypted sha1sum of the decrypted image file (yes i know, samsung devs has some kind of paranoia but no plan about real security)

Hi arris,

Do you think it is possible to trick the update process into downgrading by modifying the version and signatures?

On my BD 7500 (http://www.samsung.com/uk/support/model ... -downloads), I tried to modify the content of the files that mention the version of the firmware (currently have 1007, changed everything to 1009) but I get message "no file available to upgrade".
Would you be able to change the signature files so that and older firmware (http://drivers.softpedia.com/downloadTa ... 0+Firmware) be simulated as a much newer one (1009 or more) and make it "upgradeable"?

I guess there will be more and more people that will be annoyed by the nice features added on the newer firmware updates so if this works, it would be a great help to anyone.

Thanks!

[arris69]

...
Hi arris,

Do you think it is possible to trick the update process into downgrading by modifying the version and signatures?

if you have a rooted device then maybe you can patch exeDSP to bypass signature/version check.
the sense of cryptographic signature is that you can not manipulate the data/signature without the correct key, so i don't think that you can manipulate version/signature for usb update

[Shhhh]

Thanks a lot for the explanations... I guess it's bad luck for me now (+ a good lesson not to upgrade fw when everything works...)