AWS EC2 F2 Shell Errata
=======================

Implementation Restrictions
---------------------------

- PCIE AXI4 interfaces between Custom Logic(CL) and Shell(SH) have
  following restrictions:

  - All PCIe transactions must adhere to the PCIe base spec
  - 4-KByte address boundary for all transactions (PCIe restriction)
  - Multiple outstanding outbound PCIe read transactions with same ID is
    not supported
  - PCIe extended tag not supported. Read-request is limited to 32
    outstanding
  - Address must match DoubleWord(DW) address of the transaction
  - WSTRB (write strobe) must reflect appropriate valid bytes for AXI
    write beats
  - Only increment burst type is supported
  - AXI lock, memory type, protection type, quality of service (QoS) and
    region identifier are not supported
  - Transactions from the Shell to CL must complete within the timeout
    period to avoid transaction termination by the Shell
  - DMA transactions from the Shell to CL must complete within the
    timeout period to avoid transaction termination and invalid data
    returned for the DMA transaction
  - PCIM and DMA-PCIS AXI4 interfaces do not support AxSIZE other than
    3'b110 (64B)

Unsupported Features
--------------------

- HBM metrics not yet supported

Known Bugs/Issues
-----------------

- HBM ECC Scrubbing is not supported in Small Shell `0x10212415`:

  - DO NOT enable the "Enable ECC Scrubbing" or the
    "Initialize Memory Using ECC" option in the HBM IP. Enabling either option
    will cause an HBM monitor interface timeout during AFI loading, making the
    HBM inaccessible. Refer to `AWS Shell Interface Specification
    <./AWS_Shell_Interface_Specification.html>`__ for details.

  - ECC protection remains available. Developers can enable only the
    "Enable ECC Correction" option in the IP configuration to use it.
    **Note: Reading from uninitialized memory locations will result
    in ECC errors**.

  - Support for the "Enable ECC Scrubbing" and "Initialize Memory Using ECC"
    options will be added in a future shell release.