Please help soft-bricked, how can I fix this?

A

AC Question

Please help soft-bricked

Hello Everyone. I need some help with restoring my shield because I seem to have soft-bricked it. Last week I rooted and installed a custom recovery file and all was well but this past weekend I was messing around with it trying to install the custom rom for full android and I think I accidentally deleted the boot file and the recovery file because all I get is the android on his back with the red triangle. Also, when I try to connect to the unit using fastboot nothing is found but I DO get a hit if I put the unit in stock recovery, it gives me the option to click apply update from adb.

From what I have been reading it sounds like I should be able to sideload the recovery and/or the stock firmware. Can anyone confirm or provide me with instructions on how to get this unit back up and running.

Any help is greatly appreciated