I just upload the tutorial for Radiometric Correction. I think this may help you to adjust the data. It contains Radiometric correction, Atmospheric Correction ( sun angle correction, Landsat 7 fixline error).
Landsat data of Kathmandu: https://drive.google.com/open?id=1A42...
Download Landsat Toolbox:
https://drive.google.com/open?id=1q8g...
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Find me on GitHub: https://github.com/iamtekson