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AM6442: Clarification on OID .8 Debug Extension Fields for AM64x

ZHEN BEI SIN
Prodigy 50 points

Part Number: AM6442

We are implementing support for the System Firmware Debug Extension (OID 1.3.6.1.4.1.294.1.8) and would like some clarification regarding the values that should be used for AM64x devices.

The extension is defined as:
UID-Debug ::= SEQUENCE
{
uid OCTET STRING, -- unique ID of the device for which this certificate applies
debugCtrl INTEGER, -- debug control information
coreDbgEn INTEGER, -- Core IDs for which debug must be enabled
coreDbgSecEn INTEGER -- Core IDs for which secure debug must be enabled
}


Could you please clarify the following points for AM64x regarding the System Firmware Debug Extension (OID .8)?

1. uid Field

The documentation states:

"If the board configuration allows a wildcard JTAG unlock, set this field to a 256-bit all-zero value, which skips the SoC UID match."

Is my understanding correct that setting the uid field to 256 bits of zeros disables the device-specific UID check and allows the certificate to be used on any compatible device?

2. Secure Debug Unlock OTP Extension

Could you provide guidance on how to populate the Secure Debug Unlock related fields in the OTP extension?

3. coreDbgEn and coreDbgSecEn

Referring to the AM64x Processor Descriptor Table, I would like to enable debug access for all AM64x processors.

I am planning to use:
coreDbgEn = INTEGER:0x21201807060201  #enables Non-Secure debug for all processors.
coreDbgSecEn = INTEGER:0x21201807060201 #enables Secure debug for all processors.

Could you please confirm:

  • Are these values correct for enabling debug on all AM64x processors?
  • Does the INTEGER field support a value of this size/format (0x21201807060201)?
  • Is there any recommended encoding or formatting requirement for these fields in the certificate configuration?