Has anyone come across the LGU format?

Question

reverse engineering

There is a Renault Medianav radio tape recorder, nee LG LAN5200WR
There are updates to it, they are in files with the lgu extension File format in
short:
Header starting with LGU0, at offset 0x008, most likely the data start location, at 0x00C file size, 0x018 CRC of the archive (tempo file when creating lgu has such a CRC), then everything and starting from 0x400 comes the body
The body begins with the word Rar! And it would seem that everything should end there, but that's not it. Behind the "rar" is encrypted information.
The lgu2dir program (the author of the program does not appear on the forum for about a year) turns the lgu file into a password-protected zip, which lies at a pace and then extracts everything from it.
The bottom line is that a "new" version of the Medianav Evolution radio has been released and it has a slightly different upgrade.lgu file format. In addition to cosmetic changes in the header, the body of the archive has also changed.
Instead of Rar! there is now PK and all the same encrypted data.
IDA free draws beautifully and you can roughly understand where everything is, since there are some exceptions in the program, such as an incorrect entire file or a broken archive in a file.
I am attaching an archive with test.lgu, as well as programs lgu2dir and dir2lgu
rghost.ru/7WtBsbfSx
UPD:
ZIP password:
I_LOVE_LG^^

Answer 1

He asked, he answered:
The files are encrypted xor
Key rghost.ru/75pCsHPFJ
In the picture, an example of decryption by the application from the radio:
The key is torn out from there.

Answer 2

Hello.
New version can be found here forum.xda-developers.com/showpost.php?p=60925526&p...
Regards from France :-)
Hello.
You can find the new version here
forum.xda-developers.com/showpost.php?p=60925526&p...
Regards from France