Sorry to bug, but could you elaborate on some of the README?

[hanetzer]

So. I get the concept of this well enough. Problem is, I have no idea how to build the DebugAgentDxe.ffs.
I'm not a complete idiot regarding this stuff, I've managed to get serialice working on the device
(unfortunately it never seems to get beyond the 'firstboot' ryzen machines do), so I was hoping to try a
different approach.

Also, the preprocessor macro you say to redefine doesn't seem to be in use anymore.

[hanetzer]

Ah, figured out the preproccessor bit.

diff --git a/SourceLevelDebugPkg/SourceLevelDebugPkg.dec b/SourceLevelDebugPkg/SourceLevelDebugPkg.dec
index 564aca6e7c..a32a544398 100644
--- a/SourceLevelDebugPkg/SourceLevelDebugPkg.dec
+++ b/SourceLevelDebugPkg/SourceLevelDebugPkg.dec
@@ -111,7 +111,7 @@
   #  For example, a value of 0x00000004 stands for revision 0.4.
   #  Debug packet compression and decompression is supported since revision 0.4.
   # @Prompt Default revision of the debug agent transfer protocol.
-  gEfiSourceLevelDebugPkgTokenSpaceGuid.PcdTransferProtocolRevision|0x00000004|UINT32|0x0000000a
+  gEfiSourceLevelDebugPkgTokenSpaceGuid.PcdTransferProtocolRevision|0x00000003|UINT32|0x0000000a
 
 [UserExtensions.TianoCore."ExtraFiles"]
   SourceLevelDebugPkgExtra.uni