There is no real difference in the requirements between the downpayment for a BTO or resale flat.
The downpayment amount depends on whether you're taking a HDB loan (HLE) or a bank loan.
If you are taking a HDB loan (HLE) the loan can cover a maximum of 90% of the flat costs. However, HDB will require you wipe out your CPF OA first (except for $20k which can be retained for each owner), including paying for the downpayment of 10% of the purchase price.
If you take bank loan, you have the option of not using CPF at all for the downpayment. However, the downpayment is at least 25% of the purchase price, and at least 5% must be paid in cash.
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