same problem i've been having for months luckily its also a chromecast so i've been able to cast from my phone and chromebook but it's pretty annoying to not have a remote
If anybody found a solution please share it, tried soft reset, hard reset, factory reset with boo side button and nothing.
There's a tiny button on the box - I believe you need to press it for 10 seconds while holding the remote within 10 inches of it. Then look for the remote to flash (check the tiny manual lol)