I search for a Yahoo API substitute also for another reason than Zorro and I stumbled upon a site, I don't know really what to think of it. alphavantage.co offers free (you can apply a free API key) intraday, daily, weekly and monthly prices for US stock, ETFs etc. Their history e.g. of TLT goes back to 2002, of SPY back to 2001. The output format is JSON but this is to handle I guess. I did not verify the quality of their prices so far.
They declare their aim as "democratizing access to institution-grade financial analytics" but they have no address or company name on their site and even the domain name alphavantage.co is registered by an agent it seems. The IP address 216.239.36.21 of their server belongs to a Google net block. As said, I don't know how reputable they are.