iPhone X Apple Pay Suica Problem and Battery Optimization

A reader who is also experiencing Apple Pay Suica Express Transit gate errors with his iPhone X forwarded a fascinating blog post of Mobile Suica error flicker on Sony XPERIA Z5 Android devices.

There are 2 important points:

  • The Z5 Mobile Suica error flicker issue occurred after upgrading to Android 7 (Nougat)
  • The Z5 error flicker issue is resolved by turning off Stamina mode (Sony devices only) for Mobile Suica app.


On Android devices Suica functionality is controlled by the JR East Mobile Suica app. On iPhone and Apple Watch the Suica Mobile FeliCa functionality is built into iOS 11 Apple Pay.

Real life experience of iPhone X Apple Pay Suica on iOS 11.2.5 / 11.2.6 is better than previous iOS 11 versions but falls short of iOS 10.3.X iPhone 7 performance levels. Apple Pay Suica response at the transit gate with the ‘Done’ mark and Apple Pay sound is sometimes immediate, but often sluggish as if Apple Pay Suica is waking up from a deep sleep. On top of this there is error flicker.

Battery optimization is always a moving target. What works for one hardware configuration is useless for another. And there is battery life and throttling too. Here is a comparison of iPhone NFC controllers.

iFixIt teardowns of recent iPhone models
iPhone 7 / 7 Plus: NXP 67V04 NFC controller
iPhone 8 / 8 Plus: NXP 80V18 PN80V NFC controller
iPhone X: NXP 80V18 PN80V NFC controller

iOS 11.2.5 15D60
Restore image file list for iOS 11.2.5 15D60

Apple has different iOS restore images for different hardware configurations, John Gruber pointed out that iPhone X iOS is a completely different iOS:

Apple hasn’t called attention to this, but effectively there are two versions of iOS 11 — I’ll call them “iOS 11 X”, which runs only on iPhone X, and “iOS 11 Classic”, which runs on everything else.

Based on my 11.2.5 beta test experience and the Sony Z5 error flicker issue I think Apple Pay Suica Express Transit error flicker on iPhone X could be a battery optimization issue. However there is some interplay between iPhone X battery optimization, JR East transit gate readers, Suica Commuter Pass and Suica Express Transit at work, plus the fact that you only experience the issue in the field, that makes debugging error flicker challenging and difficult. At heart however Apple needs to fine tune iPhone X battery optimization and NFC controller performance for Apple Pay Suica.

Apple Pay Suica is the single most important ‘Apple exclusive’ iOS 11 feature for the Japanese market that brings new customers to iPhone. iPhone X Apple Pay Suica performance deserves Apple’s full attention to make Suica the best iPhone customer experience there is.

UPDATE: The iPhone X Suica problem may be a NFC hardware flaw. Details here.