lzma compressor to be used under windows

[asterix]

Hello,
the firmware files of gargoyle in format .lzma can be extracted under windows using the well known "7Zip" program.
This program can also compress again the firmware files into .7z files that are in fact files compressed with lzma compressor.
Nevertheless, those files cannot be used for flashing my Fonera 2.0 2100 ... I can of course use it with the FonFlash utility and flash the device, but the router cannot boot the linux, there is a "compressor error".

The working firmware files of gargoyle for the fonera are of type "LZMA:23", that is the type indicated by "7zip" in the properties of the compressed file downloaded from gargoyle web page.
If I uncompress the file and compress it with 7zip, the type indicated by "7zip" is "LZMA:21" or "LZMA:3m" depending on the choosen "dictionary size". But I cannot configure 7zip in order to generate "LZMA:23" ....is there some special for the program to generate the appropriate LZMA:23 format supported by the Fonera ?
Or is there another program I could use in order to generate the right .lzma file ?

Thank you in advance for your help and long life to gargoyle!

[asterix]

may I ask the question differently: how are the files .lzma of gargoyle generated ?
Is it under linux? Could you give me the command invoked under linux for generation of those .lzma files ?
Could I eventually use a running fonera for making this compression or do I need to boot on a small linux system on USB for example ?

[dellmerca]

LZMA2 is faster for 4-threads, if you compress big file (more than 256 MB), so 7-Zip will be able to split it to blocks. LZMA2 was created for XZ format and it includes changes that are good for that stream compression format.
Also LZMA2 is better than LZMA, if you compress already compressed data.

Dell