A solution would be to put some speakers connected to the headphone output and control the volume from them. Audio works, but always goes to the maximum.
El iMac 8,1 audio has a problem in which the volume does not change even if it indicates that it does.It works, but it detects it as a mouse and some settings for the Trackpad are not available. El MacBook5,2 trackpad is not supported.The computers affected by this problem would be algunos MacPro3,1 MacBook5,2 MacBookPro4,1 iMac8,1 Macmini3,1 and MacBookAir2,1. Macs with the Broadcom BCM4321 Wi-Fi module will not work with macOS Sierra unless the Wi-Fi card is changed. This means that we may run into some problem such as the following: We have to bear in mind that what we will be installing on an unsupported Mac is a kind of Hackintosh, that is, install Mac on a computer where we should not be able to install it, even if it is a Mac. The AUSEnabler tool, available from here!.The macOS Sierra Patch Tool, available from here!.Although it can be found online, it is best to get it by downloading it from a supported Mac. Install macOS Sierra on Unsupported Macs Requirements 2 And how do I update macOS Sierra on my unsupported Mac?.