You will have to dispose of your property in Malaysia and wait out a 30 month period before you are allowed to buy a Built-To-Order (BTO0 flat.
While you can appeal, HDB will most likely not approve your request.
Hope this answers your question.
1) It is clearly spelled under the HDB website that all applicants for BTO/SBF must not own any private residential property in Singapore or overseas.
2) You could have your personal reasons why this is not able to dispose of. It is best you write into HDB to seek approval before your application.
3) Untruth declaration is a very serious offense, it is not advisable to test the system.
Hope the above answer to your main concerns, but if there are more query, please feel free to contact me at 90110636, or email: firstname.lastname@example.org if more information is needed.
I'll be glad to assist.
Any response to our answer does not reach us.
The best way to get a follow-up is to Whatsapp or email us directly.