Transplanting upgraded hard drive into replacement Roamio?

Hi guys. Hope someone can help here... I have a Roamio 4-tuner with an upgraded 2TB hard drive (originally 500GB) that just got zapped by a lightning strike near my house. The good news is that it was under warranty and TiVo is mailing me a replacement. The TiVo still technically works but the HDMI port got fried... so I am streaming from this box to a TiVo mini as a holdover until the new TiVo gets here.

What I am trying to figure out is what I will need to do to transplant the 2TB drive...

Transplanting upgraded hard drive into replacement Roamio?

Transplanting upgraded hard drive into replacement Roamio?