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Products you've cited do implement MFI DRM themselves, like Apple's SD reader. It has an MFI DRM chip, plenty of teardowns are online. Additionally, the origin

Products you've cited do implement MFI DRM themselves, like Apple's SD reader. It has an MFI DRM chip, plenty of teardowns are online. Additionally, the original post is about USB-C storage accessories not working with the new iPad Pros. So, there's ample evidence that Apple can indeed enforce DRM over USB It's trivial to connect an MFI/USB protocol analyzer to the USB-C bus, and watch the DRM in action yourself. Cheers

eridius 8y ago
Apple's SD card reader is a Lightning accessory. Of course it has MFi. But you can plug a generic USB SD card reader in to your iPad using Apple's Lightning to USB 3 Camera Adapter and that works just fine, even though the generic USB SD card reader does not have an MFI chip. Similarly you can plug a camera in (which is the original purpose of that adapter), or an ethernet adapter, or a MIDI interface, or more, none of which have MFi chips and yet work just fine when plugged in via Apple's Lightning to USB 3 Camera Adapter. The fact that generic storage devices don't work has nothing at all to do with MFi and everything to do with the fact that iOS simply doesn't implement support for them.
- writepub 8y ago
  You are right that iOS has no native OS support for USB storage devices - precisely because Apple restricts access to them via MFI. i.e. as a storage accessory manufacturer, you need to add an MFI DRM chipset and pass MFI certification for Apple to allow a USB link with iOS. Here [1] are a scores of iOS USB flash drives (over lightning), all communicating with iOS via the USB 2.0 bulk storage protocol, after DRM-passing via the MFI chip they are forced to include in their hardware. Further - you are right that iOS doesn't support USB mass storage at the kernel layer - the accessory manufacturer is forced to write a user-space driver within the app advertised for said accessory. The iPad Pro doesn't work out of the box with over the shelf USB-C storage accessories because: 1. iOS has disabled USB mass storage at the kernel level to enforce DRM via the MFI program 2. Since off-the-shelf USB-C storage devices are unlikely to have added a $X MFI chip to their accessory, Apple's DRM simply blocks a USB 2.0 link from being established. So - in conclusion, USB Mass storage - a feature widely available in mobile, and desktop computing since the dawn of the spec has been crippled by Apple on purpose to milk money [1]: https://www.google.com/search?biw=1680&bih=939&tbm=shop&ei=bWzjW_G7IYXc0gL7jLa4DQ&q=iphone+flash+drive&oq=iphone+flash+drive&gs_l=psy-ab.3..0l6.17466.23062.0.23199.26.12.5.9.10.0.168.926.10j2.12.0....0...1c.1.64.psy-ab..0.25.863...0i10k1j0i13k1.0.vatn_BIUPiU https://www.google.com/search?biw=1680&bih=939&tbm=shop&ei=b...
  - eridius 8y ago
    The fact that iOS does not have support for generic storage devices has nothing to do with MFi. I do not understand why you think it does. It has everything to do with the fact that iOS simply never implemented support for them. Prior to the Files app existing it didn't make sense to support (because there would be no way to expose it), and Apple never added support after creating the Files app. > i.e. as a storage accessory manufacturer, you need to add an MFI DRM chipset and pass MFI certification for Apple to allow a USB link with iOS. How do you explain all of the previously-listed generic USB accessories working when plugged in via the Camera Adapter, given that they don't have MFi chips? All of the "USB flash drives" you listed aren't using a USB connector, they're using a Lightning connector. The use of the Lightning connector is what requires MFi. In theory[1], a third-party app could implement support for an actual generic USB flash drive plugged in via the Camera Adapter. And if Apple implemented OS-level support for USB storage devices, overnight all generic USB storage devices would start working with the Camera Adapter, without any MFi chips. > So - in conclusion, USB Mass storage - a feature widely available in mobile, and desktop computing since the dawn of the spec has been crippled by Apple on purpose to milk money If the purpose was to extract MFi licensing fees, Apple would have implemented support for attached storage in either the OS or the Files app and simply required the MFi chip. That would have allowed a third-party ecosystem of attached storage for iOS to exist. But Apple hasn't done either of these things, and until your link, I literally had no idea anyone even bothered to make flash drives with lightning connectors (given that this requires the use of a custom third-party app to use). I'm actually quite curious what happens if you use the USB connector on one of those drives, plugged in via the Camera Adapter, with the relevant third-party app. USB mass storage doesn't exist on iOS because, prior to the Files app existing, there was no exposed concept of a user-accessible filesystem and therefore no way to expose the USB mass storage to the user. Since the introduction of the Files app, it would be quite nice if Apple were to support USB mass storage as a location in Files, but it seems they never thought it was worth doing (probably in no small part due to the need for the Camera Adapter to even plug in a USB storage device; now that we have a USB-C iPad the argument is stronger for adding support to Files for this). This restriction is entirely a consequence of Apple's reluctance to have a user-visible filesystem and not related to the MFi program. [1] I say "in theory" because I don't actually know if the appropriate APIs for talking to generic USB devices plugged in via the Camera Adapter are available for use by third parties. I'm not sure what those APIs would be (having never implemented a USB driver myself) so I don't know what to search for. It is of course possible that Apple has restricted the ability for third-party apps to talk to arbitrary non-OS-supported accessories to the MFi program, but the ability for third-party apps to implement support for arbitrary accessories isn't really the point of contention here.

eridius 8y ago

Apple's SD card reader is a Lightning accessory. Of course it has MFi. But you can plug a generic USB SD card reader in to your iPad using Apple's Lightning to USB 3 Camera Adapter and that works just fine, even though the generic USB SD card reader does not have an MFI chip. Similarly you can plug a camera in (which is the original purpose of that adapter), or an ethernet adapter, or a MIDI interface, or more, none of which have MFi chips and yet work just fine when plugged in via Apple's Lightning to USB 3 Camera Adapter. The fact that generic storage devices don't work has nothing at all to do with MFi and everything to do with the fact that iOS simply doesn't implement support for them.

writepub 8y ago
You are right that iOS has no native OS support for USB storage devices - precisely because Apple restricts access to them via MFI. i.e. as a storage accessory manufacturer, you need to add an MFI DRM chipset and pass MFI certification for Apple to allow a USB link with iOS. Here [1] are a scores of iOS USB flash drives (over lightning), all communicating with iOS via the USB 2.0 bulk storage protocol, after DRM-passing via the MFI chip they are forced to include in their hardware. Further - you are right that iOS doesn't support USB mass storage at the kernel layer - the accessory manufacturer is forced to write a user-space driver within the app advertised for said accessory. The iPad Pro doesn't work out of the box with over the shelf USB-C storage accessories because: 1. iOS has disabled USB mass storage at the kernel level to enforce DRM via the MFI program 2. Since off-the-shelf USB-C storage devices are unlikely to have added a $X MFI chip to their accessory, Apple's DRM simply blocks a USB 2.0 link from being established. So - in conclusion, USB Mass storage - a feature widely available in mobile, and desktop computing since the dawn of the spec has been crippled by Apple on purpose to milk money [1]: https://www.google.com/search?biw=1680&bih=939&tbm=shop&ei=bWzjW_G7IYXc0gL7jLa4DQ&q=iphone+flash+drive&oq=iphone+flash+drive&gs_l=psy-ab.3..0l6.17466.23062.0.23199.26.12.5.9.10.0.168.926.10j2.12.0....0...1c.1.64.psy-ab..0.25.863...0i10k1j0i13k1.0.vatn_BIUPiU https://www.google.com/search?biw=1680&bih=939&tbm=shop&ei=b...
- eridius 8y ago
  The fact that iOS does not have support for generic storage devices has nothing to do with MFi. I do not understand why you think it does. It has everything to do with the fact that iOS simply never implemented support for them. Prior to the Files app existing it didn't make sense to support (because there would be no way to expose it), and Apple never added support after creating the Files app. > i.e. as a storage accessory manufacturer, you need to add an MFI DRM chipset and pass MFI certification for Apple to allow a USB link with iOS. How do you explain all of the previously-listed generic USB accessories working when plugged in via the Camera Adapter, given that they don't have MFi chips? All of the "USB flash drives" you listed aren't using a USB connector, they're using a Lightning connector. The use of the Lightning connector is what requires MFi. In theory[1], a third-party app could implement support for an actual generic USB flash drive plugged in via the Camera Adapter. And if Apple implemented OS-level support for USB storage devices, overnight all generic USB storage devices would start working with the Camera Adapter, without any MFi chips. > So - in conclusion, USB Mass storage - a feature widely available in mobile, and desktop computing since the dawn of the spec has been crippled by Apple on purpose to milk money If the purpose was to extract MFi licensing fees, Apple would have implemented support for attached storage in either the OS or the Files app and simply required the MFi chip. That would have allowed a third-party ecosystem of attached storage for iOS to exist. But Apple hasn't done either of these things, and until your link, I literally had no idea anyone even bothered to make flash drives with lightning connectors (given that this requires the use of a custom third-party app to use). I'm actually quite curious what happens if you use the USB connector on one of those drives, plugged in via the Camera Adapter, with the relevant third-party app. USB mass storage doesn't exist on iOS because, prior to the Files app existing, there was no exposed concept of a user-accessible filesystem and therefore no way to expose the USB mass storage to the user. Since the introduction of the Files app, it would be quite nice if Apple were to support USB mass storage as a location in Files, but it seems they never thought it was worth doing (probably in no small part due to the need for the Camera Adapter to even plug in a USB storage device; now that we have a USB-C iPad the argument is stronger for adding support to Files for this). This restriction is entirely a consequence of Apple's reluctance to have a user-visible filesystem and not related to the MFi program. [1] I say "in theory" because I don't actually know if the appropriate APIs for talking to generic USB devices plugged in via the Camera Adapter are available for use by third parties. I'm not sure what those APIs would be (having never implemented a USB driver myself) so I don't know what to search for. It is of course possible that Apple has restricted the ability for third-party apps to talk to arbitrary non-OS-supported accessories to the MFi program, but the ability for third-party apps to implement support for arbitrary accessories isn't really the point of contention here.