Orange Pi Zero's clockrate issue

Quang-vip

I left my Orange Pi Zero unpowered for weeks. And now when I power it up, I realized that its clockrate is no longer 1.2ghz maximum. Instead, it is 1.008ghz (I checked it using armbianmonitor) :v Well, before it got underclocked, I did nothing, but to shut it down so that I can make an enclosure for it. I'm using Armbian 5.73 stable with the kernel being 4.19.20-sunxi. Do you have any explanation for this problem?.. Or perhaps do you have any solutions for this? Any help would be appreciated!