For example:
=> ubifsls
- 17442 Thu Jan 01 02:57:38 1970 imx28-evk.dtb
- 2998146 Thu Jan 01 02:57:43 1970 zImage
+ 17442 Thu Jan 01 02:57:38 1970 imx28-evk.dtb
+ 2998146 Thu Jan 01 02:57:43 1970 zImage
And the ubifsload command allows you to load a file from a UBI