Ok, like they say, curiosity kills the cat! Since DJI refused to do a one-to-one swap on our first Action 4 camera with hot or dead pixels during long exposures, we were very unhappy with the level of service and support given. Although a Loan Unit was issued while our first unit was sent in for evaluation, it was also found with hot/dead pixels. After a lot of nonsense and lip services from various avenues of DJI support, we retrieved our flawed unit and gotten a return and refund initiated, thanks to Lazada consumer protection.
We admit we're being stupid to buy and try another unit, knowing that support is non-existential, but we just can't help it. For the content, for the information, and for our knowledge. We are not asking for a return or swap this time because it is highly likely the next unit will also present same problems. Just hope DJI will fix this hot or dead pixel problem during long exposure as soon as possible. Meanwhile, we will wait patiently for new firmware fix.