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macrumors bot
Original poster
Apr 12, 2001

It's been a while since Reserve Strap last updated its customers on the status of the device's shipping estimates, but a recent change to the Apple Watch's accessory port functionality in watchOS 2.0.1 has essentially left the band defunct and unable to ship to those who pre-ordered last summer.

In each of the band's design mock-ups, the device would have connected to the accessory port on the bottom side of the Apple Watch casing to provide up to an estimated 30 hours of extra battery life. But, as developer Lane Musgrave mentioned in a recent blog post, a lesser-known update in watchOS 2.0.1 has blocked off third-party band manufacturers from taking advantage of the accessory port to fuel the abilities of "smartbands."

The three iterations of Reserve Strap​
Beginning with watchOS 2.0.1 an unexpected change to the Apple External Accessory Protocol disabled the functionality of Reserve Strap. Until this change, Reserve Strap functioned perfectly-extending the battery life of Apple Watch by over 150% in many cases allowing users to keep their Watch charged for up to a week.

Specifically, this bug interferes with the communication between accessories and Apple Watch. For the time being, Apple has suspended use of this port until they unveil an official MFi program for Watch. In keeping with their wishes we will also be suspending shipment of all orders until Apple supports development of smartbands.
The developers note that any user who has yet to upgrade to 2.0.1, and seemingly doesn't plan on doing so in the future, can still take advantage of Reserve Strap. The company will ship a device to those customers "in the next few weeks." It's also encouraging users to send an email to the Apple Hardware Evangelism team, and submit feedback on, to spread awareness about the lack of an official Apple Watch smartband MFi program.

In March, Reserve Strap also announced the "Reserve Strap LTE," which would allow users to bypass the Apple Watch's need of a Bluetooth-connected iPhone thanks to a micro-SIM card & low power WiFi hotspot built directly into the band. Since the LTE version of the Reserve Strap uses a hotspot to connect to the Apple Watch and wouldn't necessarily require connecting through the accessory port, it could possibly move forward as a full-fledged product, but it's in very early R&D stages at this point.

The company is hoping that an MFi program will launch soon, and looks to a recent patent filing by Apple as a potential indicator of such a move. The patent describes a series of strap designs that have embedded electronic devices -- including batteries, displays, and GPS sensors -- that all connect to the Apple Watch's diagnostics port, hinting that the company could be opening the floodgates to third-party smartband developers in the future.

Given that Apple just launched a new array of bands, and has yet to suggest smartbands could be coming to the first-generation Apple Watch, it's likely such a feature would debut on future versions of the device, such as the Apple Watch 2.

Article Link: 'Reserve Strap' Suspends Shipments of All Orders Due to Apple Watch Accessory Port Policy Change


macrumors 65816
Sep 20, 2002
Should allow direct data access instead of the need for a wifi workaround for adding LTE.

Also, adding GPS via a band would be a nice feature..


macrumors 603
May 14, 2012
You wonder why I don't update right away. Now you know. iOS 8 and aOS 1 are just fine.


macrumors 68000
Mar 10, 2005
Los Angeles, California
I have no sympathy for them. That port was never designed for accessories. It's like building software around a known security bug and being mad when Apple takes it away. Doesn't sound like a legitimate business to me. Plus asking customers not to update their Apple Watch software? Yea, ok.


macrumors G3
Sep 20, 2006
There & Back Again
It's a great idea, but they can't blame Apple for wanting to close out a security flaw. I hope they do give official permission for people to use the port at some later stage so we can create more functionality on the watch but without a compromise in security.


macrumors G5
Jun 27, 2007
Pretty sure I called this when I first heard about it. You can't base your whole business on using undocumented ports. It reminds me of Palm back when they decided to hack USB protocols with iTunes to allow WebOS devices to sync to iTunes. Apple kept patching it up, shutting them down. But this is even worse because the entire business is dependent on it. Hopefully Apple launches an official program with Watch OS 3 later this year and we can hear all about it in June at WWDC. I'm suprised something like that wasn't in Watch OS 2 SDK. It's weird that Apple Watch shipped with that port if they never intended for it to be used.

Mac 128

macrumors 603
Apr 16, 2015
I guess I didn't really read how this thing was going to work. I thought it used a magnetic coil that merely passed the power through the inductive method already approved for the watch. I mean why else does it have that stupid back plate?

Apple clearly has plans for the port, so it's better to stop them now, than before thousands of customers pay for them and then complain to Apple after they stop working, when Apple denies the specs for their documented use. Every customer should demand their money back now, since it's unlikely to ever work the way the company planned.

I don't actually see this port remaining the same in the next gen watch anyway, so this band likely won't fit or work with it. I suppose it could continue to work with existing watches which haven't upgraded, but all it will take is one cool upgrade opening up new great features to motivate the user. And using it is likely to void all warranties -- I'm sure Apple has a way to determine if the "diagnostic" port has been used.


macrumors 6502
Sep 17, 2011
I believe Apple is right on this one..there are health and safety issues involved here. These things could explode while wearing them.
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