Technical question regarding thunderbolt 5 apple cables, older iMacs, new M4 studio, device updates.

[shinseiromeo]

Currently own a 2017 iMac fully loaded. It’s on its last legs and I have a BTO m4 max 1tb studio on the way, plus purchased some Apple OEM tb5 cables already. Recently I wanted to backup and clean install iOS 18.4 on my iPhone 15 pro max. Using the oem TB5 cable in my 15 pro max, the restore failed to load the ipsw file while plugged into my old 2017 iMac. The only fix was to use a standard apple USB-c cable instead of a TB5 one.

Was this error due to the older iMac not having TB5, even though the usage was just an iPhone restore/update? My entire idea behind this is leaving the TB5 cables plugged into the back of the M4 studio for my external drives, and to update my numerous apple devices such as iPhones and iPads. Or whenever updating or using a non thunderbolt device, do I have to just use a standard USB-c cable? I thought using a TB5 cable would be a ‘master’ universal wire.

 

[b17777]

Not sure about the apple cable but I do this with an OWC TB4 cable. Always plugged in for my phone and iPad backups and charging my iPad.

 

[shinseiromeo]

Not sure about the apple cable but I do this with an OWC TB4 cable. Always plugged in for my phone and iPad backups and charging my iPad.

What Mac were you connected to when doing this? For me, I was using the TB5 cable in my 2017 iMac and the restore failed every time I’m wondering to do the test once I get the m4 max studio and try to do a clean install for the iPhone to see if it works or fails.

My worry is you cannot use a ‘fancy’ TB5 cable for basic data transfer or ipsw installs for iPhone/ipad.

 

[Chancha]

I routinely backup my iPhone 15 Pro Max to a Mac Studio M1 Max base via a TB4 cable, which isn't Apple's but with one that came with Acasis NVMe enclosure.

I also happen to have an iMac 2017 at home but never tried doing the same. But I do remember the iMac being extra picky in what cables can be used, when I was connecting an iPad Pro M1 to it for either sync / backup or Sidecar I forgot. Ended up using a generic USB4 20Gbps cable instead of a TB cable.

 

[b17777]

What Mac were you connected to when doing this? For me, I was using the TB5 cable in my 2017 iMac and the restore failed every time I’m wondering to do the test once I get the m4 max studio and try to do a clean install for the iPhone to see if it works or fails.

My worry is you cannot use a ‘fancy’ TB5 cable for basic data transfer or ipsw installs for iPhone/ipad.

M1 Max Studio, my previous 2012 iMac used USB A to Lightning

 

[shinseiromeo]

I routinely backup my iPhone 15 Pro Max to a Mac Studio M1 Max base via a TB4 cable, which isn't Apple's but with one that came with Acasis NVMe enclosure.

I also happen to have an iMac 2017 at home but never tried doing the same. But I do remember the iMac being extra picky in what cables can be used, when I was connecting an iPad Pro M1 to it for either sync / backup or Sidecar I forgot. Ended up using a generic USB4 20Gbps cable instead of a TB cable.

That seems to be the case for me too. When I connected my 15 Pro max to the 2017 iMac with the thunderbolt 5 cable, it recognized the device without issue. The ipsw downloaded in finder, yet as soon as the install started, it hung and failed, disconnecting the iPhone. The only fix was to use a regular usb-c cable.

I’m hoping overall I can just plug in my TB5 cables and use them universally, and not have to use ‘lesser’ usb-c cables for basic things such as data transfer and iPhone/iPad updates and installs.

 

[PaulD-UK]

When TB4/USB4 was introduced a subsequent MacOS update was needed to make older Intel Macs compatible with USB4 devices. TB4 worked I think, but USB4 initially didn’t.

The new TB5 standard uses the same TB3/4 passive cables if they’re under 0.8m long, and high quality. But longer cables need a new TB5-specific active retiming chip.

So it maybe the software patch that was applied to allow USB4 compatibility hasn’t been updated to work with Active TB5 cables?

As a comparison, I have found that some old USB 3.0 enclosures with JMicron controllers won’t work with my TB4 cables, when connected to a Mac with USB4 ports (a single external display M1 ‘TB3/USB4’ Mac.)

 

[PaulD-UK]

@shinseiromeo Is your iMac running MacOS 15 Sequoia? Apparently that is needed for Intel Macs to have TB5 compatibility.
This might also include active cables, since the USB 3.x signal is ‘tunnelled’ within the TB data stream.

 

[shinseiromeo]

@shinseiromeo Is your iMac running MacOS 15 Sequoia? Apparently that is needed for Intel Macs to have TB5 compatibility.
This might also include active cables, since the USB 3.x signal is ‘tunnelled’ within the TB data stream.

No. I don’t recall the current macOS, though I believe it’s from two years ago. My model is a higher tier 2017 iMac 27 inch though it stopped updating in 2022.

What you’re saying definitely makes sense. It has to be an intel/old macOS compatibility issue. My hope is I can just use the TB5 cables as a universal usb-c cable going forward.