Run diskutil list again and determine the device node assigned to your flash media (e.g.

Run diskutil list to get the current list of devices.

dmg extension as necessary, mv ~/path/to/target.img

dmg ending on the output file automatically. img using the convert option of hdiutil (e.g., hdiutil convert -format UDRW -o ~/path/to/target.img ~/path/to/ubuntu.iso) Open the Terminal (in /Applications/Utilities/ or query Terminal in Spotlight).Well, disable it, restart your MacOS, do the changes and then don't forget to enable it again.Directly from the How to install Ubuntu on MacBook using USB Stick page

basically, you need to restart your mac in recovery mode, go to menu utilities and open terminal, type crsutil status to check if it is enabled or disabled, then you can use csrutil disable or csrutil enable. Obs.: if your MacOS complain, you need to disable the CSR before change this. That's it, now when you open the Bootcamp assistant you can use the option that allows you to create a USB install boot disk. it will ask if you want to replace it, then you answer yes. Save this file, go back to the contents of the Boot Camp Assistant and drag the newly edited file into. In my case I changed from Macbook7,2 to MacBookPro8,2. If it is like PreUSBBootSupportedModels, change the name to USBBootSupportedModels, expand this line and at the item0, edit and write down your MacBook model as a string value. Open this ist file with a plist file editor or xcode, then look for a line saying 'USBBootSupportedModels'.

Then find the file ist and drag and drop to a whatever folder you created before. go to your application>utilities, select the Boot Camp Assistant app, right click > show packages content. So, for those who can't create the USB install disk, here some tip.

Mac os iso to usb