Custome Linux distro for commercial Purpose

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http://stackoverflow.com – I have created one Linux distro (iso image) from scratch using Buildroot, On top of that I have ported my application, Now I want to distribute it commercial, However Buildroot using lots of packages to build linux iso, which are GPL, BSD, MIT license. Now as some of them are GPL, GPLV2 powered software, Can I use those packages commercially? Do I need to supply all license with my distro? Because in mobile I can able to see all license in 'About OpenSource' tab. One more thing I have patched some of the code, Do I also need to distribute my modified source code with the client? I have work (HowTos)