The Toronto Transit Commission says software has been updated on its fleet of articulated buses and they are back in service for the morning rush hour.  

The repair was required after unexpected acceleration was discovered Thursday during routine maintenance. 

Brad Ross, spokesperson for the TTC, said Friday that means service is normal on all bus routes.

Ross said 125 articulated buses have been updated. Morning service requires that number of buses for service to be normal.

On Thursday, the TTC pulled 153 of the 60-foot so-called bendy buses off the road. It advised the manufacturer, Nova Bus, of the issue.

In a news release, the TTC had said an operator returning to Malvern Garage experienced a "full throttle," or unexpected acceleration, and had to quickly regain control of a bus. 

No injuries were reported and no customers were on the bus at the time.

The TTC said the software fix by Nova, the bus manufacturer, takes about 20 minutes per bus to complete.

There are articulated buses on the following routes: 7 Bathurst, 29 Dufferin, 36 Finch West, 85 Sheppard East, 53 Steeles Express, and 41 Keele.