In the National Football League’s march toward technology, Bill Belichick is calling a timeout.

The New England Patriots coach says he’s “done” with Microsoft’s Surface tablets, the devices that line NFL sidelines during games to help players and coaches review images of past plays.

“They’re just too undependable for me,” he said in a rant at a press conference that reporter Zack Cox of NESN clocked at 5 minutes, 25 seconds long. The tirade eventually touched on a range of Belichick’s concerns with the NFL’s technology regime.

Belichick, a winner of four Super Bowls, including the championship game in 2015 against the Seattle Seahawks, says he’ll stick with paper printouts from here on out. Microsoft in 2014 inked a five-year sponsorship deal with the NFL for a reported $400 million. The agreement’s most visible elements are the Surface tablets, which sit in coach and commentary booths and line NFL sidelines during games. The devices, designed to be tougher than consumer versions of the tablet, occasionally make headlines when players’ frustration boils over on the sidelines.

As with Belichick’s complaints, Microsoft also occasionally fields questions about the reliability of the devices. In one past instance, Microsoft said issues attributed to the device are actually the fault of network connectivity, not Surface hardware or software failures.

In a statement, Microsoft said it respected Belichick’s decision but “stands behind the reliability of Surface.” The company said it has received positive feedback on the devices, and works with the NFL to address technical issues on the sidelines.