Proper RCW/PBI boot sequence

[dstepanov]

LX2160A Reference Manual (Rev. 0RH, 07/2020) in detailed Power-On reset description (4.9.5, table 11) states that initially Service processor loads RCW (stage 13) and only after that loads and executes PBI commands (stage 18).

But my XSPI flash image (generated using solidrun’s BSP GitHub - SolidRun/lx2160a_build: Scripts to build basic images for LX2160A COM express type 7 module...) at 0 offset contains PBI Image Preamble (bytes 55 AA 55 AA) which defines that it is a PBI block (not RCW). And the first PBI command - loading RCW (bytes 00 00 10 80).
So actually after power-on reset Service Processor first executes PBI commands and the first PBI command is to load RCW. This contradicts with description in user’s manual. What is the proper RCW/PBI boot order?

[yipingwang · Accepted solution]

This command loads the 1024 bit Reset Configuration Word from the interface specified by Power-on Reset Configuration strapping pins (POR Config pins).
The RCW will generally always be present, though it is possible to specify through POR configuration pin strapping that a hardcoded RCW value is to be used by the hardware. In this case the service processor will not look for an RCW.