With the Earlgrey-PROD.M5 milestone, all hardware IP blocks and the Earlgrey top level have reached the final maturity state for the production tapeout. This includes a limited and final set of important RTL modifications. With Earlgrey-PROD.M5, the final ROM for the production tapeout has been released.

The main changes since Earlgrey-PROD.M4 are:

• The version number of all hardware IP blocks got updated (#23969) to correctly reflect potential patches, minor and major version changes with respect to the engineering sample release (Earlgrey-M2.5.2-RC0). (This won’t be visible in silicon but in documentation.)
• The error outputs for the prim_count (#24125) and the prim_esc_receiver (#24127) primitives are now registered to avoid combinatorial glitches on those signals, thereby preventing potential CDC issues.
• The power-on reset pad is now configured with the pull-up setting enabled (#24124).
• Ibex no longer incorrectly masks ECC checks from the register file after resolving load data hazards (#24021). This issue in the Ibex repository (lowRISC/Ibex#2188) has been raised and the corresponding RTL patch has been provided by Vincent Ulitzsch, Konrad Jansen, Niclas Kühnapfel (all TU Berlin - Security In Telecommunications), and Peter Deutsch (MIT).
• RV_DM now correctly resets the TAP to the Test-Logic-Reset state (#24018).
• ROM changes:
  • An additional, lightweight FI countermeasure has been added to the ECDSA-P256 sigverify routine of OTBN (#23921).
  • The HMAC driver no longer sends multiple Process commands to the hardware per message (#24030).