IOS249 means exactly nothing. You can install every IOS and every cIOS as IOS249, IOS249 only means that a ÂIOS is installed at position 249 in the Wii's nand.
You can get the needed files for the installer via wifi during installation, or you can download them at your pc from nintendo's servers(WiiGator) or you can extract it from a game disc with wufe(Waninkoko).