Here are some suggestions of things you can do to aggressively help yourself get qualified for a mortgage loan in California, even with a bad credit history:
Pull your credit and review it.
Pulling your own credit will not negatively affect your credit score like having someone else pull it will. Look over your credit history and make sure that everything has been reported accurately. Something as small as an account being reported as currently being instead of being included in a past bankruptcy can be the difference of 10-15 or more added points to your credit score.
If you have small collection accounts, try to pay them off and then fax confirmation that the account was paid off to the major credit bureaus so that they can adjust your credit report right away.
Make sure every account that is closed is reported as being closed. Make sure that every account that was reported in a bankruptcy is reported that way, and not being reported as money still owed.
Editing this information on your credit report is easier than ever today because all three major credit bureaus now make it possible to dispute inaccuracies online.
Find a seller who is motivated to pay closing costs or carry back a percentage of the loan.
If you find a seller who is really motivated to work with you, that may help you get approved with a lender. If the seller can pay your closing costs, it will free up that money so you can have a small down payment. If the seller is willing to carry back a percentage of the loan then the loan-to-value may be low enough that the lender may consider that as good as a down payment.
If the seller is motivated to work with you, they may be willing to work through a down payment assistance program to help you make a down payment. It is illegal for a seller to give you the down payment for their house, but through down payment assistance programs like Neighborhood Gold and the Nehemiah program, it is legal.
Borrow or ask for a gift from relatives toward a down payment.
After you have financed your house, you can usually take out a second or third mortgage up to the full value of your house repay your relatives. Keep in mind that if you intend the money to be as a loan from your relatives, you need to disclose that to the lender. Lenders usually have regulations about where the down payment is coming from and if you are not honest, it could be considered defrauding a lender.