I wrote the Raspbian Stretch image with Desktop to my USB HDD using Win32 Disk Imager. I resized partition 2 using
sudo fdisk /dev/sda (my usb drive) by deleting the partition and recreating it with the same start and a new end (the default one of fdisk) on my Pi 3 that has Jessie installed.
After rebooting I expanded the filesystem of partition 2 by executing
sudo resize2fs /dev/sda2.
df -h showed that everything went right. I deleted all partitions on a 4GB SD card, created a new "W95 FAT32 (LBA)" partition (both steps using fdisk), created a new vfat filesystem (
sudo mkfs.vfat -F 32 /dev/sda1, my HDD wasn't attached) and copied the files from the HDD's boot partition to my SD card.
I changed the cmdline.txt's
root option on my SD card to
root=/dev/sda2. So my cmdline.txt now looks like that:
dwc_otg.lpm_enable=0 console=serial0,115200 console=tty1 root=/dev/sda2 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait quiet init=/usr/lib/raspi-config/init_resize.sh splash plymouth.ignore-serial-consoles
After trying to boot from the SD card with the HDD attached the Raspberry Pi logos at the top of the screen appear and after about 14 seconds when the HDD is ready those messages are printed:
[ xxx.xxx] sd 1:0:0:0: [sda] No Caching mode page found [ xxx.xxx] sd 1:0:0:0: [sda] Assuming drive cache: write through
They are also printed when executing
dmesg on Jessie.
After these messages the Pi reboots, again showing the rainbow screen, and everything starts again.
I don't want to boot from USB by setting an OTP-bit because I still want to be able to boot from SD card.
Is it possible that my HDD spins up to slow (14 seconds are quite a bit)?