From https://www.ifixit.com/News/46508/can-diy-storage-save-you-money-on-the-series-x-probably-not, via https://www.ifixit.com/Teardown/Xbox+Series+X+Teardown/138451?vgo_ee=VtJ79grfqv26ndtk9UYjHL35hO7C/F3J/gQB9Uu3XAY=#s275577:
Despite actually using M.2 storage internally, software locks complicate the replacement, and the 2230 size is hard to find online.
- The storage is a standard, albeit rare, format: 1 TB of m.2 2230 NVMe SSD
- It’s likely running under a newer spec, PCIe Gen 4.0
- It’s partitioned just like the storage in the Xbox One


Despite actually using M.2 storage internally, software locks complicate the replacement, and the 2230 size is hard to find online.