Could not find the root block device in .

[XenonBlue]

I get this error when trying to reboot into gentoo after initial install. When I type in /dev/sd4, where my root directory is, the boot begins again for a few seconds then the screen goes black, as in there's no output to my monitor and it goes to sleep. I am dual booting with Windows 10, I have full functionality of Windows 10 and rEFInd AFAIK. I'm thinking maybe the /boot is too small, but it's shared with Windows and I couldn't resize the partion in Windows so for fear of messing things up I avoided resizing it in parted.

my kernel: genkernel-x86_64-4.9.76-gentoo-r1

my boot manager: rEFInd

blkid from live cd

[DONAHUE]

The windows provided 100 MB EFI Systems Partition (ESP) has been more than adequate on several multiboot machines here.
Sounds like a kernel configuration problem.
Recommend:
boot the install media, preferably system rescue cd/usb, and mount the gentoo partitions
run:
lspci -k | wgetpaste -t
wgetpaste -t /mnt/gentoo/usr/src/linux/.config
parted -l | wgetpaste -t
post the url's returned and lets take a look.
_________________
Defund the FCC.

[NeddySeagoon]

XenonBlue,

Welcome to Gentoo.

[XenonBlue]

parted -l : https://paste.pound-python.org/show/EoTqwN1AyBn3Ideshqbd/

lspci -knn : https://paste.pound-python.org/show/RgctLvz6cMMfjNL2ibNh/

kernel .config: https://paste.pound-python.org/show/m1TjUgv4QjvkzlwbiM4s/

[DONAHUE]

Do you have an initramfs? If you do, it apparently is not being executed.
The genkernel configuration you posted has "CONFIG_SATA_AHCI=m". If there is no initramfs or if an existing initramfs is not executing the "Could not find the root block device in ." would be explained.
Graphics support section of the configuration: decide between proprietary (follow https://wiki.gentoo.org/wiki/NVidia/nvidia-drivers#Kernel ) or open source (follow https://wiki.gentoo.org/wiki/Nouveau )video drivers.
genkernel --menuconfig or cd /usr/src/linux; make menuconfig will provide the opportunity to edit the kernel configuration. Recommend using one or the other and editing the disk drivers and file systems required for booting to builtin instead of module. Then reconfigure the graphics support section to conform to the wiki for your choice of video driver. In the subsection " Frame buffer hardware drivers" the only choice that should be enabled is "[*] EFI-based Framebuffer Support". I've posted my nouveau graphics support configuration at https://paste.pound-python.org/show/T4mlXDQ635oZBVWqPapd/ .
Enable "<M> EFI Variable Support via sysfs " under "EFI (Extensible Firmware Interface) Support --->" which is under "Firmware Drivers --->"
Recommend enable "[*] Built-in kernel command line
(root=PARTLABEL=rootfs ro) Built-in kernel command string
[*] Built-in command line overrides boot loader arguments" under "Processor type and features --->"
After the configuration changes are made, ensure the boot partition is mounted, then allow genkernel to finish (if genkernel --menuconfig is used) or run "make && make modules_install && make install" (if genkernel is not used), rEFInd should find and run the EFI stub kernel in /boot.
_________________
Defund the FCC.

[NeddySeagoon]

XenonBlue,

What DONAHUE said about initrds.

The kernel and optional initrd together mush be able to mount root.
If you choose to not use an initrd, the kernel binary as loaded from /boot has to mount root on its own.
That means all the the code to find and reed the root filesystem must be configured as <*>.

<m> means put the module in /lib/modules/ on the root filesystem, which can't be read until root is mounted.

How did you make your kernel and optional initrd?
What does your boot loader say about loading the kernel and initrd?
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.