Maru uses android-prepare-vendor to generate a complete vendor tree for angler, including vendor.img. This allows you to flash your build without having to first flash the latest stock image. If your build hangs on the Google boot logo, please ensure that you have generated a complete vendor tree with android-prepare-vendor.
If you want to use an alternative method of obtaining the vendor files that does not generate vendor.img, see this PR for an easy workaround.
See the main Maru OS repository for more info.