SAO PAULO, Aug 14 (Reuters) - Brazilian telecom firm Oi SA proposed amendments to its restructuring plan on Friday, urging creditors to extend new loans and to get higher bids for assets put on the block.

Creditors will vote on the proposed changes on Sept. 8, as Oi plans to exit bankruptcy protection by May 2022, roughly six years after starting the process.

"After lots of talks, we concluded that the plan needed some more flexibility than initially foreseen," Chief Executive Rodrigo de Abreu said in an interview.

Oi set the floor on bids for its fiber unit at 20 billion reais ($3.7 billion) in enterprise value. It is selling a 51% controlling stake in the fiber unit, known as InfraCo, and plans to auction it in the first quarter and conclude the sale by September 2021.

For the mobile assets, Oi decided to include long-term contracts - for 3, 5 or 10 years - with its fiber unit in the total price offered by bidders. Abreu said these contracts tend to increase InfraCo's value.

Oi is in exclusive talks with TIM Participacoes SA , Telefonica Brasil and America Movil's Claro which delivered a joint 16.5 billion reais bid for the mobile assets. If they reach an agreement, the telecom providers will have the right to match any other higher bid for bankrupt Oi's cellular operations that other parties could make later.

Oi also decided to sell its TV operation for 20 million reais, in a move to eliminate more significant satellite costs. Still, the acquirer will share some revenues with Oi, as it will continue to offer TV services to its clients.

Oi is also offering creditors to pay more on their current debt if they extend new loans or letters of guarantees to the company. The proposed haircut may fall to up to 40% from 60% if creditors provide Oi with fresh money, for instance.

($1 = 5.40 reais) (Reporting by Carolina Mandl; Editing by Richard Chang)