Hello TF-A mail list,

I'm new here, so I quickly introduce myself. I am Florian Manoel, working as firmware developer at Siemens in Karlsruhe, Germany. Recently, we decided to start some development based on ARM processor, the theme TF-A is new for us.

Currently, we have a custom board equipped with the processor NXP Layerscape LS1043a. So far, everything is working as planned, the PreBootLoader (TF-A) boots the bootloader (U-Boot) that's boots linux on top. However, we want to have the possibility to boot an alternative u-boot FIP image, I explain: We use as boot source a QSPI NOR memory. In this memory are stored 'bl2_qspi.pbl', 2 times 'fip.bin', the u-boot environment and some micro-code. We want to select the u-boot image to be booted according to the value of a specific variable stored in the u-boot environment 'u-boot-select'. The algo is, for my eye, relatively simple :

Start - Check value of the u-boot variable 'u-boot-select'

- Check if the corresponding u-boot image is valid, if not select the alternative one - Boot selected u-boot image End

We want this functionality in case an u-boot image is broken (ex: power OFF during U-Boot update).

I already went through the source code and it rose more question than it answered. For example: I noticed that TF-A is designed to load FIP Image but the U-Boot Environment have a different format. How to access the QSPI NOR memory? NXP specific driver? The bl2 is designed to load only one FIP image, is it possible to add an additional entry ? On top of it come the question of the reliability and what will happen if we want to use a secure boot in the future..

I am looking for advice and support on this specific topic. Thanks for your support,

Mit freundlichen Grüßen Florian Manoël

Siemens AG Digital Industries Process Automation Software House Khe DI PA CI R&D 2 Östliche Rheinbrückenstr. 50 76187 Karlsruhe, Deutschland Tel.: +49 721 595-1433 mailto:florian.manoel@siemens.com www.siemens.com/ingenuityforlifehttps://siemens.com/ingenuityforlife

Siemens Aktiengesellschaft: Vorsitzender des Aufsichtsrats: Jim Hagemann Snabe; Vorstand: Joe Kaeser, Vorsitzender; Roland Busch, Klaus Helmrich, Cedrik Neike, Ralf P. Thomas; Sitz der Gesellschaft: Berlin und München, Deutschland; Registergericht: Berlin Charlottenburg, HRB 12300, München, HRB 6684; WEEE-Reg.-Nr. DE 23691322