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skorefish
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PostPosted: Tue Jul 14, 2015 6:35 am    Post subject: [solved]not mount vfs unknown blockdevice/ X55A on usb drive Reply with quote

I 'm trying to install gentoo on my X55A Assus, booting from a sitecom 5in1 usb drive with 32 gb sandisk micro sd..


GRUB 2 BOOTS starts the kernel but the kernel can't find the usb drive. It is possible to start my fsroot with System rescue where i can recompile my kernel over and over again.

I tried a lot of settings, USB,SATA,SCSI,... But as always kernel panic: can't mount fsroot.

Is there somthing more to do, to boot from this usb combination?


Last edited by skorefish on Tue Jul 21, 2015 8:20 am; edited 1 time in total
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DawgG
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PostPosted: Tue Jul 14, 2015 9:45 am    Post subject: Reply with quote

you have to compile everything usb-drive-related into the kernel (not as modules).
then you probably have to play around with different grub-settings (root-device) and /etc/fstab as well. those multi-readers always claim a device even if there ist no "disk" (card) in the slot, and grub might "see" this differently than the (booted) kernel.
i have a box with two "normal" disks and a usb-reader, and grub (0.97, no initrd) has the setting root=/dev/sda5 whereas the system boots correctly only with the setting root /dev/sde5 in /etc/fstab.
it might help to use fs-labels or UUIDs in your case.
(if you want to save yourself some trouble you might use a simple, one-slot reader.)
GOOD LUCK!
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Roman_Gruber
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PostPosted: Tue Jul 14, 2015 9:56 am    Post subject: Reply with quote

check lsmod and /proc/config.gz or what it is called and extract the needed settings.

afaik sysrescuecd is gentoo based anyway
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NeddySeagoon
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PostPosted: Tue Jul 14, 2015 10:05 am    Post subject: Reply with quote

skorefish,

Grub finds and loads the kernel so thats all good.
In the normal course of events, root is mounted before the USB subsystem is stared.
Thats a very bad thing if root is on USB.

You need
Code:
rootdelay=7
on the kernel line in the bootloader configuration file to allow the kernel USB stuff to start before root is mounted. The 7 is seconds. Values between 5 and 30 are usually good.
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skorefish
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PostPosted: Tue Jul 14, 2015 10:16 am    Post subject: Reply with quote

ok, I 'm I the grub.cfg and find this line

Code:
 linux   /vmlinuz-4.0.5-gentoo root=/dev/sdc4 ro


what does this exactly do? Is this responsible for loading the kernel or the rootFS?
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NeddySeagoon
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PostPosted: Tue Jul 14, 2015 10:27 am    Post subject: Reply with quote

skorefish,

It does both.
Code:
linux   /vmlinuz-4.0.5-gentoo
Tells grub to load the file /vmlinuz-4.0.5-gentoo, (with respect to grubs root) and that the file is to get control when grub exits.
Code:
root=/dev/sdc4 ro
is passed to the kernel to tell the kernel what to do. In this case use sdc4 as the root filesystem and mount it read only. You need to add the rootdelay here.

See
Code:
cat /proc/cmdline
I get
Code:
root=/dev/sda3 video=intelfb:mttr:3,ywrap,1024x600-32@60 net.ifnames=0

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skorefish
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PostPosted: Tue Jul 14, 2015 10:28 am    Post subject: Reply with quote

Neddy,

do you mean like this
Code:
 linux   /vmlinuz-4.0.5-gentoo root=/dev/sdc4 ro rootdelay=7
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NeddySeagoon
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PostPosted: Tue Jul 14, 2015 11:18 am    Post subject: Reply with quote

skorefish,

Did it work, or at least, change the error?
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skorefish
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PostPosted: Tue Jul 14, 2015 12:10 pm    Post subject: Reply with quote

Neddy,

Yes, it changes. When I boot I can see the usb2/3 drivers, the scsi drivers and even the name of my usb card.
it recognises sdc4 but then again kernel panic.

then I changed the uid by /dev/sd(b,c)4 my rootfs is on sdb4 when I do my grub2-mkconfig

the result was different: something about sleep mode: I think this is something of win8 (I think), it also talks about ntfs
a lot of numbers filling the screen (sort of machine code ???)
the can not mount unknown block error but now with a number in it

When I remove my drive it says drive removed, and it also recognizes it when I put it back in..
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NeddySeagoon
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PostPosted: Tue Jul 14, 2015 12:51 pm    Post subject: Reply with quote

skorefish,

Its still panicing. I suspect that the drive letter is changing between install and reboot.
You can either use trial and error, which is quite fast.
At the grub menu press 'e' to get into edit mode.
follow the on screen instructions to try sda3...sdd3 or however many drives you have.
This only edits the in RAM grub.cfg.

You could also use root=PARTID= or root=UUID=
The latter requires the use of an initrd. blkid will list your PARTIDs and UUIDs.

Once it boots fix the bootloader config file and /etc/fstab
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skorefish
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PostPosted: Tue Jul 14, 2015 2:17 pm    Post subject: Reply with quote

This is very odd, on my Toshiba it boots on the X55A not!

what do we learn from this? Is it still a kernel config problem ?
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skorefish
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PostPosted: Tue Jul 14, 2015 5:04 pm    Post subject: Reply with quote

Ok I have some more info. Well it boots and then you see only hex numbers but when I remove my usb device it complains it can not read ext4.
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NeddySeagoon
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PostPosted: Tue Jul 14, 2015 6:04 pm    Post subject: Reply with quote

skorefish,

The hex numbers indicate a kernel panic.

Is there something more like
Code:
unknown-block(x,y)
where x and y are numbers?
What are the numbers?

What about
Code:
Unable to find root block device in.

The kernel will list all the block devices it can see between the in and .
It looks a bit odd if the list is empty.

As you still loaded a kernel with the USB device disconnected, how did that happen?
It means tha you are not booting from USB. There is nothing wrong with that if its what you intended.

How did you build your kernel?
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DONAHUE
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PostPosted: Tue Jul 14, 2015 6:17 pm    Post subject: Reply with quote

windows8 was mentioned.
status of secureboot? uefi?
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PostPosted: Tue Jul 14, 2015 6:19 pm    Post subject: Reply with quote

DONAHUE,

It was loading and executing a kernel
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skorefish
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PostPosted: Wed Jul 15, 2015 11:44 am    Post subject: Reply with quote

Quote:
As you still loaded a kernel with the USB device disconnected, how did that happen?


after loading and seeing the numbers, nothing happened, then I removed the usb.


Yes it's uefi? I opened up my computer and removed the harddrive.
I still see a kind of firmware and same result when booting. (the numbers on the screen)

can uefi load from rom? I know w8 can be very fast booting the harddrive. I press esc but don't see any firmware.
I think it's uefi with bios emulation

I found this http://www.ubuntu.com/certification/hardware/201206-11376/ (about asus x55A)

and reading this article about uefi
https://www.happyassassin.net/2014/01/25/uefi-boot-how-does-that-actually-work-then/

Quote:
When a system's software interface between the operating system and firmware is UEFI (instead of BIOS), GPT is almost mandatory as compatibility issues will arise with MBR here.
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NeddySeagoon
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PostPosted: Wed Jul 15, 2015 1:31 pm    Post subject: Reply with quote

skorefish,

Your kernel loads. After that happens the BIOS, boot loader (if any) and UEFI are irrelevant.
Its just the kernel and the initrd if you have one, in the whole of RAM.
The BIOS/UEFI and bootloader are all about loading the kernel and passing control to it.

Post the output of blkid and tell what each partition is for. Tell which is the usb-storage device.
Post the output of lspci
Post your grub.cfg
Post your kernel .config and tell how you have been builing your kenel.

Make friends with wgetpaste
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skorefish
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PostPosted: Wed Jul 15, 2015 2:04 pm    Post subject: Reply with quote

Neddy,

oh no, I already reformatted for uefi, I 'm gone play with that now for a while.
If this doesn't work I 'll come back to the MBR formatted one. Now its GPT with fat32 for uefi.
But uefi is all new for me.

But a question about the root. Is it a problem I just copied it from my Toshiba hd to my x55a usb drive.
Do I need some recompilation ??

Sure I 'll send the info when ready.

I started up with systemrescueCD -> 5 boot existing Linux partition

I did make defconfig and then make localyesconfig, then I screwed around with make menuconfig
make -j3; make install
grub2-install /dev/sdc
grub2-mkconfig -o /boot/grub/grub.cfg -> edit grub.cfg rootdelay=7
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skorefish
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PostPosted: Thu Jul 16, 2015 5:31 am    Post subject: Reply with quote

hi, I'm back with gpt/bios/grub

I did a genkernel all now
It boots then complains: Block Device /dev/sdb4 is not a valid root device, and some options to choose another device
then i type /dev/sdb4 and it starts :roll: 8O
fstab https://bpaste.net/show/430b57f55cc7
dmesg:
https://bpaste.net/show/2037364bd193

lspci:
https://bpaste.net/show/8adcf5a8f9e3

lsmod
https://bpaste.net/show/f033f8e67692

grub.cfg:

https://bpaste.net/show/c6b9d3f6cd02

I had to boot my systemRescueCd to send this message cause i have no networksupport

dmesg of sRCd: https://bpaste.net/show/ed8c4d639940
lspci of sRCd: https://bpaste.net/show/74ed95958c25
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NeddySeagoon
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PostPosted: Thu Jul 16, 2015 7:38 am    Post subject: Reply with quote

skorefish,

skorefish wrote:
But a question about the root. Is it a problem I just copied it from my Toshiba hd to my x55a usb drive.
Do I need some recompilation ??


Maybe. As well as all the things in your kernel you need to boot normally, you also need USB and usb-storage support to boot from USB. If you made the USB options as <M> and do not have an initrd, you must rebuild your kernel.
When you select an option as <*> its built into the kernel binary loaded by grub.
When you select an option as <M> the binary is in /lib/modules/... which is on the root filesystem which can only be read after root is mounted. You say you copied the kernel from elsewhere ... did you also cp -a /lib/modules/ ?
Not that copying modules will help you to mount root, its another learning experience.

grub.cfg:
      echo   'Loading Linux x86_64-4.0.5-gentoo ...'
      linux   /kernel-genkernel-x86_64-4.0.5-gentoo root=UUID=415daa18-9cd7-4fbd-958c-b5ae0881c1c5 ro 
      echo   'Loading initial ramdisk ...'
      initrd   /initramfs-genkernel-x86_64-4.0.5-gentoo

grub.cfg shows you used genkernel but the rootdelay=7 is missing from the kernel line. I don't know if genkernel produces a suitable kernel for USB booting but I suspect it does.
skorefish wrote:
It boots then complains: Block Device /dev/sdb4 is not a valid root device, and some options to choose another devicethen i type /dev/sdb4 and it starts

You are doing the rootdelay by hand :)
You wait for mounting root to fail, USB gets started while you read the message and enter the root partition again, this time it works.
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skorefish
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PostPosted: Thu Jul 16, 2015 3:35 pm    Post subject: Reply with quote

hi,
I did a new make menuconfig, and changed
Code:
 rootdelay=3 rw
int the grub.cfg 2 is also possible 1, is to fast

this works, if i keep
Code:
ro
then its says,
Quote:
freeing unused kernel memory and stops...


Now i have to check for the network card. This means menuconfig, :wink:

after that i 'm very intersted in the distcc ... seems a very cool feature 8)
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