First up you should not just assume or believe that you have a unacceptably bad credit history and need a Non Conforming Loan. If you have been slow at paying in the past you might be surprised to learn that most people have at some time and often it’s not because they haven’t got the money to pay, they were focused on something else at the time. What you think is bad might be considered average by your lender. And even if it is, or was, bad it may not be the end of the discussion because there are other options particularly so if you are buying your home and have equity in it.
Historically austere banks kept people with a slow or bad credit history at a distance. Pooling credit data so that they, as a club, could exclude such people from accessing the financial system.

In later years new non bank financial institutions came along and realised that they could make money selling higher margin loans to higher risk prospects and even began to eat into some of the banks traditional clients with friendly prompt service. These days’ credit laws and privacy laws take account of the fact that people get more responsible with borrowings as they get older, and that people also deserve a chance to change their ways, and so the law makes it harder for financial institutions to keep people down, if they once had a difficult credit history period. Many financiers, including banks, now participate with products that enable borrowers to get a fresh start and eventually return to prime borrower status with the best interest rates.

Banks have changed in other ways too. They are profit driven and willing to charge you whatever they can get away with. They also have been criticised in recent years for everything you can imagine and no longer care if taking on 100 marginal mortgage loans ensures that they will be criticised for selling up the homes of some of those borrows, if the overall portfolio is profitable for them, because the rates are higher and the security will mostly cover the loans that fail. Mostly a credit score system will approve your loan and if they can establish that you are a real person with a real job then your small credit card and personal loan facilities get processed promptly