Uploading some debugging info, I am having the same issue on 9.10 alternative cd.
my boot options: cdrom-detect/try-usb=true persistent file=/cdrom/test/test.seed debian-installer/locale=en_US.UTF-8 console-setup/layoutcode=us initrd=/install/initrd.gz DEBCONF_DEBUG=developer quiet rootdelay=10
(tried to see if rootdelay works, but you can remove this and it still happens)
Uploading some debugging info, I am having the same issue on 9.10 alternative cd.
my boot options: try-usb= true persistent file=/cdrom/ test/test. seed debian- installer/ locale= en_US.UTF- 8 console- setup/layoutcod e=us initrd= /install/ initrd. gz DEBCONF_ DEBUG=developer quiet rootdelay=10
cdrom-detect/
(tried to see if rootdelay works, but you can remove this and it still happens)