uboot/tools/binman/test/22_image_name.dts

/dts-v1/;

/ {
	#address-cells = <1>;
	#size-cells = <1>;

	binman {
		multiple-images;
		image1 {
			filename = "test-name";
			u-boot {
			};
		};

		image2 {
			filename = "test-name.xx";
			u-boot {
			};
		};
	};
};