The only way to get unlocked iPhones is to buy full price at official Apple Online/Retail Store. All unlocked iPhones can now be used anywhere in the world, regardless of supported bands. 

Also, to people who are buying from China or Hong Kong: Be warned that the model number for sale in Malaysia (A1778/A1784) is different from the iPhones sold there. Same goes for Japan or US iPhones too (unless you go with AT&T or T-Mobile).

However, in most cases you can't submit them for warranty claim at Malaysian AASPs. You definitely won't get support for those other models here in Malaysia, since AASPs are only allowed to order replacement devices with model numbers sold locally. For those models, you will have to go Singapore cuz only Apple Asia HQ can override that policy.

Now you must consider pros and cons, here's a handy chart (with explanation below):

Model	Sold in	AASP support	Network support	FeliCa support
A1660/A1661	HK/US/ZH	No	CDMA^, GSM*	No
A1778/A1784	MY/SG/WW	Yes	GSM	No
A1779/A1785	JP	No	GSM, CDMA	Yes

^ A1660/A1661 (CDMA) [Sold in US]:  Not supported locally, but has more network bands. Can be used on CDMA carriers like Verizon or Sprint. Can't support FeliCa.

* A1660/A1661 (GSM) [Sold in HK/ZH]:  Not supported locally, but has more network bands. Can't be used on CDMA carriers like Sprint in US or SoftBank in Japan. Can't support FeliCa.

A1778/1784 [Sold in AU/MY/SG/worldwide]:  Supported by local AASPs, but has less network bands. Can't be used on CDMA carriers like Verizon in US or SoftBank in Japan. Can't support FeliCa.

A1779/1785 [Sold only in JP]:  Not supported locally, can be used with CDMA carriers like SoftBank in Japan, can't turn off camera shutter sound, but supports FeliCa (which is Japan's version Touch N Go. It's literally everywhere there) so you can use e-money cards like Suica with Apple Pay.

i got some advice for whoever planning to buy iphone or ipad from oversea.
since every country might get different model/product code.
there is something you guys need to know.

apple make the product to comply the law or rules and regulation for every single country.
some are hardware and some are software even packaging are different, not every iphone/ipad are the same

example:-
japan - iphone and ipad which selling in japan are unable to mute the photo capture sound ("ka-cha" sound) no matter you mute your phone or not and no single setting to mute that sound too. not just only iphone actually most of the camera and phone selling in japan have to comply this policy.

Kingdom of saudi arabia - remember few years ago, i got a customer which purchasing her ipad from Dubai. but she found out the facetime feature are not install on her ipad. and facetime is not able to download from app store since it was part of the ios.

we tried to restore her ipad to latest os we had that time, but the ios detect her ipad is ksa model so the facetime still not able to show in her ipad.

you can search on google for "missing facetime app"

hope this can help.