RP2350 Never Runs Boot Stage 2 #10248
Labels
Milestone
Comments
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
{{ message }}
At startup, RP2350-based boards do not run boot stage 2. This is due to a change in the way
_stage2_boot()is invoked. For the RP2040, boot stage 2 was invoked directly by boot ROM. For the RP2350, stage 2 is invoked bycrt0.Sunder the control ofPICO_EMBED_XIP_SETUP. Since CP does not setPICO_EMBED_XIP_SETUP, it defaults to 0, causing_stage2_boot()to not be copied onto the stack and executed. See raspberrypi/pico-sdk#1903.RP2350 boot ROM tests flash, selecting XIP parameters automatically, including the clock divider and one of four XIP modes (two serial modes, a dual mode, and a quad mode). This obviates the need for boot stage 2 for normal clocking cases. Since CP has been running successfully without boot stage 2, it's clear that it is not needed at this time.
However, this could be an issue for overclocking and flash writes as discussed in the referenced Pico SDK issue. Boot ROM exits from flash writes with flash timing and mode set to its automatically determined values, overriding any changes that may have been made for overclocking.
I'm filing this issue so that this detail doesn't get lost.
The text was updated successfully, but these errors were encountered: