Is that 100% reproducible? Which version of QEMU did you use here? And which host are you using, POWER9 again? The very latest git master branch is using a timeout of 10 minutes now, so that should be sufficient for all cases...
Could you please try to run this manually:
qemu-system-sparc64 -nographic -M sun4u -prom-env 'use-nvramrc?=true' -prom-env 'nvramrc=." Hello World!" cr'
... and then paste the output here?
Is that 100% reproducible? Which version of QEMU did you use here? And which host are you using, POWER9 again? The very latest git master branch is using a timeout of 10 minutes now, so that should be sufficient for all cases...
Could you please try to run this manually:
qemu-system-sparc64 -nographic -M sun4u -prom-env 'use-nvramrc?=true' -prom-env 'nvramrc=." Hello World!" cr'
... and then paste the output here?