The name used for compressor during compression in arc.ini must be same for decompression end too, for example :
xzlib+srep+lzma2:ultra:64m:bt4:fb273:lc8:mc1000000
Code:
[External compressor:xzlib]
header = 0
unpackcmd = xtool.exe decode -t100p - - <stdin> <stdout>
if method is xzlib+srep+lzma2:ultra:64m:bt4:fb273:lc8:mc1000000
and it is set like this :
Code:
[External compressor:xtool_zlib]
header = 0
unpackcmd = xtool.exe decode -t100p - - <stdin> <stdout>
The installer won't detect it. Set the same for lzma2, it uses 7z and use CLS-SREP for srep.