* Hello guys. I'm still having trouble installing GrapheneOS on my Pixel 4a.  I'm using Linux Mint and when I try to flash the image in the terminal it says:
> ./flash-all.sh: 22: [: Illegal number: 1:81
> fastboot too old; please download the latest version at https://developer.android.com/studio/releases/platform-tools.html

I made sure I updated to the latest version of fastboot by following these instructions: https://idroot.us/install-adb-and-fastboot-ubuntu-20-04/
No change though. Any suggestions? 

Should I try installing from Windows 10 instead? Would there be security issues with using Windows 10 since it's closed source? FYI, Signify doesn't work on Debian based distros and I'm using one.