HSS build process vs hss-payload-generator

[pcrosemurgy]

Reading the top-level HSS README.md I see how the HSS binary is built and flashed to eNVM.

However, I'm having trouble understanding how the hss-payload-generator relates to this top-level build process. From hss-payload-generator/README.md it sounds like it produces a binary that can also be flashed to eNVM. Is there a high-level explanation for how these two build processes relate to one another?

It seems like the hss-payload-generator must be used if you want to flash an HSS with a custom u-boot.bin payload to eNVM?

Thanks!

[hughbreslin]

Hey @pcrosemurgy

The HSS runs from eNVM, due to the size of the eNVM not much else can fit in there with it (128KB). The HSS payload generator creates payloads with headers which can be booted from external non-volatile memory, like eMMC, SD cards etc. The payload generator is not part of the HSS build process but is actually part of the embedded software build process.

I would suggest having a look at this document on the tool flow and also this document which describes HSS payloads.