Hi,

With the commit right before c219c22cbd[1], my rockpro64 (ARM 64bit
SBC) boots fine and I get a login prompt both on the attached display
and serial port.

With c219c22cbd[1] instead it blocks here (see the attached boot.log
file for the full boot log):
> [   33.762050] avdd: disabling

I've attached the system.scm file I used for the test. It's being
reused by a machine configuration in another file (rockpro64.scm) and
I deploys the configuration with:
> guix time-machine --commit=$(GUIX_COMMIT) -- deploy -L . rockpro64.scm

References:
-----------
[1] commit c219c22cbdb62ba52b50ec8fb12bebce0b1dd459
    gnu: shepherd@0.10: Use guile-fibers 1.3.1.
    * gnu/packages/admin.scm (shepherd-0.10)[native-inputs, inputs]:
      Replace GUILE-FIBERS-1.1 with GUILE-FIBERS-1.3.

Denis.