https://koreantech.org/android-%ed%9c%b4%eb%8c%80%ec%a0%84%ed%99%94%ec%97%90%ec%84%9c-%ed%84%b0%ec%b9%98-%ec%9e%85%eb%a0%a5%ec%9d%84-%eb%b9%84%ed%99%9c%ec%84%b1%ed%99%94%ed%95%98%eb%8a%94-%eb%b0%a9%eb%b2%95-no-root/