Blame the router, not the ISP
In MF285, Susan Platter couldn’t download OS X. One possibility could be that she has a BT modem/router. All their models more than two years old block downloads exceeding 4GB. I experienced this and resolved it with a new modem. However the new one had no VoIP facility, so I now have to swap between two models! John Marsh
That’s a good point, John. Some older modems, especially the BT Home Hub have had problems with Internet Recovery in the past. Some of them actually stall after just 53MB. Most of us stick with the same broadband provider for years and years, through sheer inertia. There’s really no excuse for this. Once you have a Gmail or iCloud email address that isn’t tied to a specific broadband company, you can switch providers with a minimum of fuss. If you stay with the same bank or electricity company for too long, you might be missing out on the best deals. But if you don’t change broadband provider every few years, you might also find yourself stuck with out of date router hardware. Most companies only send you a new router when you first sign up. So when your initial contract comes up for renewal, it’s definitely worth getting in touch with your provider even if you don’t plan to switch, and asking them for a new modem.
Yosemite is over 5GB to download and older broadband routers may block it.