How to create a Bootable Mavericks installation USB?
Step 1: Download DiskMaker X here. Run “DiskMaker X”, then choose “Mavericks (10.9)” when you are asked which version of OS X you want to make a boot disk.
Step 3: Locate and selet El Capitan installer in Applications/
Step 4: Click An 8GB USB thumb drive
Step 5: Select the right USB then click on Choose this disk.
Step 6: Click on Erase button then create the disk
Step 7: Choose Continue and fill the administrator password when you are asked.
Step 8: Wait until the process is finished.
You now have an OS X 10.9 Mavericks installer in a bootable USB.
Step 4: Click An 8GB USB thumb drive
Step 5: Select the right USB then click on Choose this disk.
Step 6: Click on Erase button then create the disk
Step 7: Choose Continue and fill the administrator password when you are asked.
Step 8: Wait until the process is finished.
You now have an OS X 10.9 Mavericks installer in a bootable USB.