Does anybody know possible way just change asterisk default configuration files of the image (.gz file), without rebuilding it? I tried to use 7-ZIP. It allow me to change files of the image without extracting it. But when I upgraded asterisk configuration files of the image, image become unable to import into metarouter. Metarouter says "Archive is too short"
Well, it's not just a .gz (gzip) file, it's a .tgz / .tar.gz file, so it's a compressed "tarball". I have no familiarity with 7-ZIP, but a quick Google reveals it to be a Windows-based multiformat compressed archive utility. If you are modifying the tarball with 7-ZIP, and RouterOS can no longer import it after that, then it seems clear that 7-ZIP is doing something wrong, and is corrupting the file when you try to use 7-ZIP to modify the file. So...moral of the story is, don't use 7-ZIP, I guess. Something must be buggy either with its TAR support, or its GZIP support.
I have never bothered to try to modify the MetaROUTER tarball images directly, because I've had no need to. If I want to make a change, I always make it in the OpenWRT build environment. However, in theory, making your own tarball without recompiling everything should be possible. Rather than using 7-ZIP, why don't you use the actual tools that made the file in the first place? tar and gzip. Decompress the file somewhere, make the changes that you want to the directory tree you unpacked from the tarball, and then recompress the entire directory tree again into a new compressed tarball.
Long term, if you are going to be making many changes, it would serve you best to teach yourself how to perform an OpenWRT build.
Second thin is, yesterday I had power issue and router rebooted. But /etc/asterisk/users.conf file has broken. Just became blank file. All other files "/etc/asterisk/extensions.conf, /etc/asterisk/extconfig.conf" are OK. How can I automate process "backup users.conf file every day and replace original users.conf by this backup file after every reboot occurs"
Sounds like an issue similar to what others were seeing with http.conf corruption after not shutting down the system cleanly. You might look back through this thread for other posts on the subject. I think some people may be creating cron jobs to schedule config backups, and then adding their own shell scripts to /etc/init.d that restore the latest backup during bootup. I haven't looked into it myself.
Quite honestly, if you are unfamiliar with basic UNIX system administration concepts (such as using tar and/or gzip, cron, shell scripts, and the init bootup process), you're probably going to have a tough time maintaining an Asterisk system. I am trying to make my MetaROUTER image as plug-and-play and "turnkey" as possible, but obviously it isn't there yet. It's a project I've been working on in my spare time and that I've voluntarily given back to the community. But I cannot reasonably be expected to support every single person that uses it, and help them make their own custom changes to it; I don't have the time to train people how to use it correctly, much less do things with it or to it that it doesn't do already. I am offering it freely "as-is", so if it serves your purposes as-is, then great! And although I welcome feedback when things don't work, as that will help make it better, if you need something other than what I've provided, you should be willing to take the time to teach yourself how to make it, and then get your hands dirty, or find someone you can pay to do what you need.