Chromebook 14 cb3-431 update trouble

PustayaPa4ka
PustayaPa4ka Member Posts: 1 New User

Hi there. 

I've messed up my new chromebook and can't find a way to fix it. I bought it in BestBuy (refurbished one). Full model name - cb3-431-c5ex. It worked fine, automatically updated a few times. A while after purchasing I've decided to switch to canary update channel, but there was no "change channel" button in settings. So I had to switch to dev mode and choose canary through command line. It worked, but after that laptop refused to boot in dev mode. Hovewer, I still could boot in normal mode, but audio dissapeared. And without dev mode I have lost opportunity to switch back to stable channel (there was no button and *shell* works only in dev). Well, OK, I just downloaded recovery media tool to my PC, created recovery USB drive and flashed it to laptop. After that I've got my laptop running 8743.85.0 build (nov 16 2016) and "change channel" button finally appeared. But there's still no sound and OS doesn't update anymore. Neither stable nor dev and beta. I stuck on this build. It seems like chrome os update servers treat my laptop as unknown modification. 

I need some advice, what can I do to make it update and to get audio to work.