FYI if you want your home to secure is not just router but PC side also.
Xiaofan above post already mentioned that routers sold or issued in SG.
These routers have been certified by IMDA as well as CSA to ensure the router
are compliant with telco standards especially against security threats etc.
Firmware level is just a software level, there are more towards Networking security
than just firmware. Telco side, vendor managing the networking equipment etc.
Not sure why are you so concern with the firmware.
While if you ask me in my field, I seen many home users PC being comprised.
Either due to never do security patching motherboard BIOS level as well as
Windows level.
Home PC security is more than just firmware if you ask me, have I seen hacker/scammer
hack a home before.
Yes I have so is not just to fault ISP or IMDA not mandating firmware
to patch router so your home will be secured.