Sometimes the "CERT.RSA" file is called something else. No idea why. I have often found the certificate file to be called something".RSA".
For example, when I decompile the "wp.wattpad" APK, it has its certificate saved as "BNDLTOOL.RSA"
My advice to you would be to find the file in the META-INF folder that has the extension ".RSA". It is probably the ...
ADB (android debug bridge)
The fastest and officially supported method to transfer files to/from an android device is via adb (Android Debug Bridge) which will be installed automatically if you install Android Studio. Once you activate Developer Options on on your phone and enable Android Debugging in settings, and connected to your android device via adb, ...
Short answer: brew cask install android-platform-tools
I was in the same case (on macOS 10.14.6):
$ fastboot devices
ERROR: Couldn't create a device interface iterator: (e00002bd)
I tried previous answers of this topic without success, so I searched which program is at the origin of fastboot command:
$ which fastboot