Can one the Thunderbolt 2 ports be used for an external SSD boot drive instead of a USB port? Are the Thunderbolt 2 ports bidirectional and capable of supporting an NVME PCIe SSD in an appropriate case? What cabling is required? Thanks, I haven’t found the answers online yet.
iMac 21.5″, macOS 12.6
Something like this Thunderbolt 3 external PCIe chassis might work, they claim it to be backwards compatible with Thunderbolt 2, but it would basically operate at half speed on your Thunderbolt 2 ports, not at Thuderbolt 3 speeds, see their fine print note:
"Thunderbolt 2/Thunderbolt compatibility requires a certified Thunderbolt 3 (USB-C) to Thunderbolt 2 (mDP) adapter and a Thunderbolt 2 cable (available separately). This configuration provides data transfer at up to 20Gb/s but does not support notebook charging."
https://eshop.macsales.com/item/OWC/HELIOS3S/
you could contact that vendor to find out more details or other options, they have good Mac support.
Something like this Thunderbolt 3 external PCIe chassis might work, they claim it to be backwards compatible with Thunderbolt 2, but it would basically operate at half speed on your Thunderbolt 2 ports, not at Thuderbolt 3 speeds, see their fine print note:
"Thunderbolt 2/Thunderbolt compatibility requires a certified Thunderbolt 3 (USB-C) to Thunderbolt 2 (mDP) adapter and a Thunderbolt 2 cable (available separately). This configuration provides data transfer at up to 20Gb/s but does not support notebook charging."
https://eshop.macsales.com/item/OWC/HELIOS3S/
you could contact that vendor to find out more details or other options, they have good Mac support.
Your iMac does not support Thunderbolt 3 or 4, it supports Thunderbolt 2. That means you would need to find a Thunderbolt 2 external SSD which you will not. You are better off using a USB 3 external SSD.
Nice find! :)👍
External SSD boot for late 2015 iMac 21.5 Retina display
