Wall Street analysts are warning their institutional investors AT&T has broken its promise to end price wars on smartphones with the announcement it will offer a free iPhone 8/8+ with the purchase of another, as long as customers also subscribe to DirecTV.

The promotion breaks a truce among wireless carriers to stop heavily discounting smartphones and other devices in bids to win over subscribers. The deal could cost AT&T between $700-800 per promotion participant, before any dealer discounts are applied. AT&T has not said whether the promotion will also extend to Apple’s ultra-deluxe iPhone X, which starts at $999. It will apply to other phones AT&T offers in its retail stores and online.

AT&T is looking to boost subscriber numbers for DirecTV and get its wireless customers to bundle television service with their phone plan. Getting a customer to commit to a term committed DirecTV subscription, especially if they have not subscribed in the past, is a high hurdle to overcome, but a free iPhone may be enough for some to take AT&T up on its offer. AT&T will even sweeten the deal with an iPad for an additional $99.99, if the customer signs a two-year wireless contract.

The promotion starts this Friday and is the first of what could be several aggressive offers targeting iPhone fans. The popular Apple device attracts scores of high income customers wireless carriers desperately want on their networks. In 2016, a vicious cutthroat price war started by T-Mobile soon dragged in almost every wireless carrier and cost at least $200 per customer in margins.

So far, T-Mobile has avoided a similar offer, content with offering customers up to $300 in trade-in-credit for iPhone 6 or newer smartphones in good condition. That credit can be spent on the iPhone 8/8+ or iPhone X. Verizon has a similar offer. Sprint is offering a “half-off lease” for the iPhone 8/8+ if a customer trades in their iPhone 7 in good condition.

Wall Street worries about equipment promotions because it can challenge carriers’ cash on hand and cut into profit margins. Since rate plans are no longer adjusted upwards to recoup the cost of the promotion, the provider has to eat the expense.