My kiddo recently got a iMac 12 mid 2011 model as a gift for homeschooling purposes. The device was working perfectly fine until the reset to remove the previous owners information as per the Apple web instructions. Holding "Options" only activates internet recovery which then is unable to reinstall - at first High Sierra. The device now wants to reinstall Lion but says <Unable to download additional components. I have a bootable drive created on a Windows PC using TransMac with High Sierra 10.13.dmg however, it does not give the option to select the USB as a bootable, it only gives internet recovery - which does not work.
When opening disk utility, the main computer drive is there as well as USB - where I can see the High Sierra drive, and then a disk1 - Mac OS X Base System - that I can do nothing to.
Any advice or steps to try and get the iMac working again? I have been at this for a couple of days now with no success, going through forums, Youtube videos and Apple support site. iStore refuses to assist with vintage device and I do not have an additional Mac available. My kiddo is 8, I really was not thinking of getting her a new iMac at this stage for the purpose and just to get use to Apple before investing further, the device was able to do everything she needed before the reset. Would appreciate any assistance here.