Chassis Fans When Booting From Flash

Hi all.

I have a HiFive Unmatched with a 1TB NVMe drive. Months ago I sorted out how to install the OS on it and boot from flash. Unfortunately when booting like this the chassis fans aren’t running. When taking an SD card with an SPL and U-boot directly from Releases · sifive/freedom-u-sdk · GitHub and changing MPSEL[3:0] back to 1011 they are fine (as in, they do run).

I’ve gotten adept at building the SPL and U-boot with these instructions HiFive Unmatched — Das U-Boot unknown version documentation and correctly flashing to /dev/mtdblock0, flip MPSEL[3:0] to 0110 - everything boots, no fans.

A few questions: is there a standalone SPL and u-boot.itb that SiFive publishes that I could try and see if there is some subtle configuration difference from when I’m building from source? Something is preventing those fans from spinning and I’m determined to find out what. :slight_smile:


EDIT: Well, it is in either the SPL or U-boot (which is what I thought to begin with). Even though I cannot get my compiled versions to turn the chassis fans, I was able to extract the delivered versions from SiFive from the SD and write straight out to flash. Remove SD, flip MSPEL[3:0] to 6 and in business. I feel a blog post coming on for this one.