Original Xbox Memory Cards on Xbox 360 — Incompatible

No. Original Xbox Memory Units (8 MB) do not work on Xbox 360.

Why

• Different form factor: Xbox MU = proprietary card slot (top of console)
• Different filesystem: FATX vs. Xbox 360's FATX variant (incompatible structures)
• Different protocol: 360 uses USB Mass Storage Class for Memory Units (MU)

Xbox 360 Storage Options

• Official 360 Memory Units: 64 MB, 256 MB, 512 MB (USB dongle form)
• USB Flash Drives: Up to 2 TB (formatted by console, max 32 GB per partition on 360 OS)
• Internal HDD: 20–500 GB (2.5" SATA, proprietary caddy)
• Cloud Saves: Xbox Live Gold required (now Game Pass Core)

Transferring Original Xbox Saves

Impossible directly. Some BC titles (e.g., Halo, Fable) recognize original Xbox saves on 360 HDD if transferred via Xbox 360 Hard Drive Transfer Cable (discontinued, rare).

Original Xbox MUs are museum pieces. Use USB drives on 360.