Videos of the incident went viral in April.
Mobile phone footage of the incident, in Heath Park Road, went viral and has divided opinion since it happened on Easter Monday, 22 April.
The two teenage boys had been approached by officers, who attempted to carry out a stop and search.
The Independent Office for Police Conduct launched an investigation after a third party made a complaint.
A spokesperson for the IOPC said: “Our independent investigation into the arrest of two teenagers in Romford on Easter Monday (22 April) is making good progress and we met with the boys’ family this week to update them.
“Several independent witness to the interaction between two police officers and the boys have been interviewed.
“Two officers have been served with notices informing them they are being investigated. One officer has been served with a criminal notice in relation to their use of force while the other has been served a notice of gross misconduct for their rationale to initiate the stop and search.
“The serving of a notice does not mean that misconduct or criminal charges will necessarily follow.”
Tags: Havering, Gidea Park