USB boot, detect correct / partition

I installed arch to my external hard drive which works fine.
The grub config point points root at /dev/sda1 and this is also in fstab to tell it to mount /dev/sda1 to /.
The problem is that when my pen drive is installed the external harddrive becomes sdb and i have to edit both these file to get a proper boot.
The same problem occurs when a pc has a sata hd - these are referred to as sda, sdb rather than hda, hdb.
How can i compensate for this so i dont have to edit grub & fstab everytime?
Ckearly distros than run off pendrives or even live cds can deal with these issues, does anyone have an idea how?

Depending on the size of the drive (whether it's a hard drive of flash drive), OS X doesn't always create an exFAT drive Windows can correctly read. Format the drive on a Windows computer. OS X will be able read/write the exFAT flash drive whether it's MBR or not.

Similar Messages

Boot from second partition on usb hard drive

I have a time machine external usb drive. I have created a second partition of 8GB on this drive and restored OS X Install ESD 10.7.5 to this second partition so that I can easily rebuild if necessary. I would like to be able to boot from this second partition. When I hold down Option key at startup, I see the external drive as an option, but the iMac wants to boot from the Time Machine Backup partition, rather than the Lion Partition. It doesn't give me the choice of the second, bootable partition on this drive. Is it possible to do this?
[Mac 24" early 2009, running 10.7.5 Lion]

rchealey wrote:
Curiously when you boot from this partition, you get virtually the exact same experience as you do when booting from the recovery partition except that the recovery partition tends to suggest that it will download and install Lion, whereas booting from the partition containing the install doesn't mention download.
That's normal behavior. The Recovery HD only has enough code to go to Apple's servers and DL the installer; whereas, the InstallESD contains everything. Do note, however, that running either will check Apple's servers for additional components, whatever those might be. Thus, Internet access is required to do either.

[SOLVED] UEFI system booting from MBR partition table and GRUB legacy

I'm trying to understand once and for all the process by which Arch can be booted from a system with UEFI firmware and an MBR partition table. Some of the information on the wiki seems conflictual / non-nonsensical at times. Apologies in advance if this has been answered time and time again, but I did search around and all I found was fixes to get Arch to boot rather than comprehensive explanations of the boot process.
Now, the way I would imagine it works is that it's just completely identical to the way it would work with a BIOS firmware. The UEFI firmware detects an MBR partitioning scheme (or is configured to know it's an MBR partitioning scheme), activates some "legacy" mode and executes the MBR boot code, just like a BIOS firmware would.
The wiki however, says different. From the Macbook article: "Do not install GRUB onto /dev/sda !!! Doing so is likely to lead to an unstable post-environment."?
So what is there in the MBR boot sector? Nothing?
How does the firmware know what to boot if there's no 0xEF BIOS boot partition and no Grub stage 1 in the MBR boot sector?
Also, how does installing Grub stage 1 to a partition work? Does it have to be at the beginning of the partition? Wouldn't that overwrite some existing data?
I'm especially puzzled since many guides to installing Vista on a macbook recommend simply formatting as MBR, and installing as normal, which I suppose entails having the Windows installation process write its boot code to the MBR, ie the equivalent of installing grub stage 1 to /dev/sda rather than to the /boot partition, as the Macbook article suggests.
Any input is appreciated.
P.S. I realize it's probably simpler, if I just want to dual boot Windows and Arch, to install Windows 7 in UEFI-GPT mode, let it create the EFI System Partition, and then install GRUB 2 to that partition, but I'm still curious about the UEFI-MBR boot process.
Last edited by padavoine (2012-06-06 09:35:10)

padavoine wrote:
CSM in UEFI firmwares do the exact same job as normal BIOS firmware.
So it's something specific to the Mac that it's able to boot from a partition's VBR while ignoring the MBR?
The reason that warning is given is because grub-legacy modifies more than just the MBR boot code region. It can overwrite some parts of GPT header.
Not true, the instruction is given in the context of an MBR format, not in the context of a GPT format, so there's nothing to overwrite and Stage 1.5 should be safely embeddable in the post-MBR gap.
In BIOS boot (normal case in non-UEFI firmwares or CSM in UEFI firmwares) does not read the partitition table (atleast it is supposed to be dumb in this regard), it simply launches whatever boot code exists in the 1st 440-byte of the MBR region.
So again, you're saying it's specific to the Mac UEFI that it lets you choose a partition whose VBR to load, regardless of what's in the MBR?
I haven't used Macs so I can't comment on Mac firmware behaviour. But normal BIOS firmwares (legacy and CSM) launch only the MBR boot code and not the partition boot code. We need some chainload capable boot manager in the MBR to launch the partition VBR.
grub-legacy does not know anything about GPT. So when you install grub-legacy to /dev/sda, it install the MBR boot code (stage1) and stage 1.5 code to the (supposed) post MBR gap. Since there is no actual post MBR gap in GPT (which has been taken over by the header and partition table), grub-legacy does not check for GPT and it assumes the post MBR gap actually exists which is invalid in case of GPT. grub-legacy embeds the stage 1.5 code in GPT header and table region (which grub assumes to be unused post MBR gap) and thus corrupts it.
0xEF is the MBR type code for UEFISYS partition. grub stage 1 (used in grub-legacy, not in grub2) is the 440-byte boot code stored in MBR for use in BIOS boot.
That's precisely my point: with neither proper executable code in the MBR (since grub was installed to a partition, not to the MBR) nor a UEFI system partition, what does the firmware default to, and how does it know what partition to boot from?
In that case it might fallback to UEFI Shell (if it exists) or give an error similar to the case where BIOS does not find any bootable code in 440-byte MBR region.
So even with bootcamp/CSM, the disk also needs to be MBR partitioned. So Macs use something called "Hybrid GPT/MBR" ( http://rodsbooks.com/gdisk/hybrid.html ) where the MBR table is synced to match the first 3 partitions in the GPT table.
I know what Bootcamp does, and that's not what I was referring to. I was referring to standalone Vista installs. I wasn't puzzled at the fact that they were using MBR, I was puzzled at the fact that contrary to the recommendations for the standalone Arch install on the wiki (with MBR partitioning, not GPT), they didn't do anything to try and prevent Windows from writing to the MBR.
You can't prevent Windows from overwriting the MBR region. You have to re-install the bootloader (grub2/syslinux etc.) after installing Windows. That is the reason why it is recommended to install Windows first and linux later.
Thats not true. I actually find it is much easier to install Windows UEFI-GPT using USB rather than a DVD.
I haven't done it since the only UEFI system I own has no DVD drive, but I was under the impression that it was simply a matter of choosing DVD UEFI boot in the firmware's boot menu.
format the USB as FAT32 and extract the iso to it. That it.
No, thats not it, precisely, it doesn't work out of the box with a standard Windows install USB, you need to fiddle around:
2.3 Extract bootmgfw.efi from [WINDOWS_x86_64_ISO]/sources/install.wim => [INSTALL.WIM]/1/Windows/Boot/EFI/bootmgfw.efi (using 7-zip aka p7zip for both the files), or copy it from C:\Windows\Boot\EFI\bootmgfw.efi from a working Windows x86_64 installation.
2.4 Copy the extracted bootmgfw.efi file to [MOUNTPOINT]/efi/microsoft/boot/bootmgfw.efi .
Most of the Windows isos already have /EFI/BOOT/BOOTX64.EFI file, so no need to extract the bootmgfw.efi file.
There is no difference between in BIOS booting in UEFI firmwares and BIOS booting with legacy firmware.
There has to be a difference, at least in the Mac firmware (sorry, I keep switching), since legacy firmware, AFAIK, cannot chainload a bootloader in a partition's VBR without there being some sort of "stage1" code in the MBR.
No idea about Mac EFI. Apple made a spagetti out of UEFI Spec. To actually understand how Mac firmwares work, read the blog posts by Matthew Garrett of Redhat, about his efforts in getting Fedora to boot in Macs.

Help, my computer refuses to boot the recovery partition.

My computer refuses to boot the recovery partition. I hit f12 during startup and selected "HDD recovery", however instead of loading what is suppsoed to be the toshiba recovery wizard, the text "HDD recovery" quickly flashes on the bottom of the screen and then it simply loads windows 7 normally.
I can access the hidden recovery partition from windows 7 and I can see the .wim file in there, but I don't know how to restore a computer using a system image. I've tried that option and it tells me it is unable to find system images, is there a specific place I have to put this file? Do I have to burn it to dvd?
I ran linux off the optical disk drive to see if it would boot anything other than windows 7 and surely enough linux worked.
I've also tried copying the contents of a system repair disk onto a usb and replacing the boot.wim with the .wim on the toshiba recovery partition and renaming it to boot.wim, which let me into the toshiba recovery wizard, but I was unable to continue past the first menu.
It says on the bottom of my laptop the specific model is a Toshiba Sattelite P750 -04S, if I've read it correctly.
Edit: Is there anyway to "start fresh" without using the recovery partititon or buying a new copy of windows? What I am trying to do is to revert to factory "out of the box" settings.

Satellite P750-04S (PSAY3C-04S010)
We support US computer at this website. Everything for your Canadian model is here.
You can order recovery discs by calling 800-663-0378. The discs are free, but the shipping and handling charges are probably substantial.
For instructions, see the section Restoring the pre-installed software from your created Recovery Media, which begins on p. 1-16 of the User's Manual (attached).
-Jerry
Attachments:
P750-P750D-P755-P755D_EnglishManual.pdf ‏4796 KB

Windows 8 does not have a USB boot option

QuestionHow can I boot my Windows 8 laptop from a USB device? I created a recovery disk on a USB thumb drive.
So far I have:
Entered into the UEFI (BIOS) and set USB to boot first.
Disabled secure boot.
I tried to reboot using the general setup options for startup in the windows settings page. I choose boot from USB through the UEFI, but got an error message that system does not have a USB boot option.
To confirm I also created a bootable DVD with an ISO burner, but my laptop cannot detect a DVD boot option either.
I assumed that the firmware of the UEFI for this computer allowed a bootable USB but in practice I cannot seem to get this work.
AnswerTo assist with not being able to boot from a USB device on a Windows 8 laptop, perform the following:
Plug in USB bootable device.
Hold down F12 when restarting and access UEFI menu (option is below drive list). If system is set to fast boot, CLICK HERE for instructions on entering the UEFI.
Go to UEFI and make USB "1st boot".
Disable secure boot.
Go to the "Advance" Tab, select "System".
Change boot order from UEFI to CSM.
Save changes and exit (F10).
Computer will restart and boot from USB drive.
When finished go back into the UEFI and set defaults then save changes and exit (F10). Windows 8 will reboot normally next reboot.

Done that, only choices are "Set up Firefox to Sync" & "Pair a Device". No ''UNLINK THIS DEVICE". Your turn.

Booting from a partitioned drive

I have 1,5 TB drive and want to create 2 partitions. One for cloning using Super Duper and second back up by data files. Is this possible? Because I read that Apple doesn't officially support booting from Apple partition map on Intel Macs and doesn't allow to install the OS X.
Thanks,

Well, after using disc utility, I had a bad luck... kernel panic during the partition. And the computer panics anytime the drive is plugged in. Firewire and USB. I tried my other computer .... the same thing. That means the drive is dead!
Oh Well...
Here is the error:
Wed May 13 09:40:58 2009
panic(cpu 2 caller 0x001F9445): "jnl: mod block start: bufsize 512 not a multiple of block size 4096\n"@/SourceCache/xnu/xnu-1228.9.59/bsd/vfs/vfs_journal.c:2282
Backtrace (CPU 2), Frame : Return Address (4 potential args on stack)
0x8d8af2a8 : 0x12b4f3 (0x45b13c 0x8d8af2dc 0x1335e4 0x0)
0x8d8af2f8 : 0x1f9445 (0x46c6e4 0x200 0x1000 0x0)
0x8d8af348 : 0x332a34 (0x9e55d10 0x7ccc7a80 0x0 0x200)
0x8d8af3e8 : 0x33be77 (0xc140004 0x1 0x0 0x8d8af778)
0x8d8af7a8 : 0x33443e (0xc140004 0xa151804 0x0 0x0)
0x8d8af8b8 : 0x335ea6 (0x0 0xb6b0364 0x0 0x0)
0x8d8af9a8 : 0x1f5d9f (0xa97a258 0x1049d8c0 0xbffffdc4 0x0)
0x8d8af9f8 : 0x1df47f (0xa97a258 0x1049d8c0 0xbffffdc4 0x0)
0x8d8aff28 : 0x1dfb40 (0xadb7ba4 0x8d8aff48 0xb6b02a4 0x1)
0x8d8aff78 : 0x3df460 (0xadb7ba4 0xb6b0260 0xb6b02a4 0x0)
0x8d8affc8 : 0x1a0887 (0xb3d97a0 0x0 0x1a30b5 0xa25e640)
No mapping exists for frame pointer
Backtrace terminated-invalid frame pointer 0xbffffe18
BSD process name corresponding to current thread: mount_hfs
Mac OS version:
9G55
Kernel version:
Darwin Kernel Version 9.6.0: Mon Nov 24 17:37:00 PST 2008; root:xnu-1228.9.59~1/RELEASE_I386
System model name: MacPro3,1 (Mac-F42C88C8)
Message was edited by: Girshon Rutstein

Creating a USB boot image for LabviewRT

I have installed Labview 8.2 and the "update 8.2.1" for Labview RT Standard version from the web.
I am trying to create a bootable image for a target Laptop PC, using a USB jump drive.
When I run NI-MAX and select TOOLS->RT Disk Utilities->Create Desktop PC Utility USB Drive, a popup dialog appears that says:
"This utility will reformat a USB drive with a Labview Real-Time boot USB utility for use with a USB boot-capable Desktop PC. Make sure the USB drive is connected to your computer before you continue.
Do you want to use this utility?"
Clicking on Yes, shows a dialog selection window, with a single entry ="Version 8.2", and an OK and Cancel button.
Selecting the OK button, shows an error popup titled: Measurement & Automation Explorer" with text="Unable to detect USB drives"
The jump drive is 32MB and is visible in WINDOWS Explorer.
WHY will NI-MAX not see or use this jump-drive ?
( I have tried two different jump drives from two different manufacturers)

Hello,
Does your jump drive conform to the USB Mass Storage Device Class? What drive letter are you using? Did you create it by running the command line utility "subst"?
Have you tried doing this on a different computer? Are the USB ports 1.1 or 2.0?
http://digital.ni.com/public.nsf/websearch/D3AD6D3474D09C5E86256E130079C1B0?OpenDocument
Regards,
Clint M
National Instruments

Creating a Mavericks USB boot drive after the horse has bolted. Can I create a bootable USB drive from my iMac after installing Mavericks without saving the Install OS X Mavericks.app file? Do I need to re- download the whole 5.29 Gb again?

Creating a Mavericks USB boot drive after the horse has bolted. Can I create a bootable USB drive from my iMac after installing Mavericks without saving the Install OS X Mavericks.app file? Do I need to re- download the whole 5.29 Gb from the App Store again? My problem is my 4Gb/month allowance on a 12 month contract. I cannot purchase a data block from my ISP and although my speed is theoretically slowed to 64k after reaching my 4Gb, it actually ceases to download in reality.

HI tasclix, it depends what you mean by an OS X boot drive.
If you want a recovery disk from which you can reinstall (by re-downloading) or recover from a time machine backup, then nbar is correct.
If, however, you want to boot and run the OS X installer from the USB drive (so that you don't need to download again), then you will need a copy of "Install OS X Mavericks.app"; see this article:
http://support.apple.com/kb/HT5856
Before downloading again, search your system to see if the installer is still there - it's usually in the /Applications folder unless it has been deleted, but check your whole system for it anyway, you never know, you might still have it somewhere.
Message was edited by: SilverSkyRat

Can I switch out a hard drive for an SSD without having to clone the existing hard drive, and then install Yosemite from an USB Boot Drive onto the new SSD?

Can I simply replace a hard drive with a new SSD and just install Yosemite from a USB boot drive onto the SSD? I recently bought a used MBP and it has absolutely no files on it except for the OS, and so I'm assuming I don't need to clone the current hard drive as I can just reinstall the OS onto the new SSD.

Honey_Revenge wrote:
Thanks.
Just a quick follow up question, is formatting the SSD with HFS+ done in Disk Utility?...
It's possible that the SSD will be set up for use on a PC, which means it will have a Master Boot Record partition table rather than a GUID Partition Table, which is what Yosemite needs. In Disk Utility, select the SSD and click the Partition button. Create a new Partition Layout and click the Options... button at the bottom. You'll likely see MBR is selected. Choose GUID instead and Mac OS Extended (Journaled) for the Format.

GS60-2QE (970M) USB Boot Issue

Hi all,
I have been having a strange issue on my new Ghost Pro, sometime it allows me to boot from a USB CD drive or thumbstick and other times it won't. I have checked the BIOS settings, secure boot, UEFI, boot order and they are fine. The USB devices show in the USB configuration section too. When saving the settings and holding F11, there is no USB boot device but occasionally there is... I can't work it out and it's most annoying or a fault?
I have flashed the BIOS to the latest 10D release but that hasn't helped. Resetting defaults makes no odds either.
Anyone got any ideas?
Thanks
Will

Quote from: thewillbowles on 14-February-15, 15:10:50
Hi all,
I have been having a strange issue on my new Ghost Pro, sometime it allows me to boot from a USB CD drive or thumbstick and other times it won't. I have checked the BIOS settings, secure boot, UEFI, boot order and they are fine. The USB devices show in the USB configuration section too. When saving the settings and holding F11, there is no USB boot device but occasionally there is... I can't work it out and it's most annoying or a fault?
I have flashed the BIOS to the latest 10D release but that hasn't helped. Resetting defaults makes no odds either.
Anyone got any ideas?
Thanks
Will
I have heard there is issues if you use a USB 2.0 cable or usb stick 2.0 it would not work 100% on USB 3.0 port for weird reasons such as installing windows 7 will just keep saying it couldnt detect the drivers thats because usb 2.0 has issues with 3.0 ports which idk why :/ so try using USB 3.0 on USB 3.0 while USB 2.0 on 2.0 than 2.0 on 3.0 then it should work

"New USB device detected" - large black window comes up & at the bottom it says "hold alt to remember the choice". How do I reset?

"New USB device detected" - large black window comes up when I plug an external HD or NetTalk device. At the bottom it says "hold alt to remember the choice". Im running Parallels 6.0, so give me the option to choose. I held alt and chose Mac. Now I want to choose Windows 7 - BootCamp, but Can't. How do I reset my choice, so it always asks me?
Thanks for your help!

You may get faster answers by also asking the Boot Camp forums area here:
Boot Camp

Cannot see correct partition for Vista

Trying to install Vista Ultimate 64 bit on a mac pro (2008) on it's own hard drive. Questions- when I installed the new drive the machine doesn't recognize it and asks me if I wanted to initialize this. Rightly or wrongly I skipped this, went to boot camp assistant, selected the newly installed hard drive and indicated that I want to create a single partition for windows, then it asked me for the windows OS,I started the install. When it came to the point where I needed to select the correct partition for windows, the correct selection according the instructions disk0partition3 bootcamp didn't show up as an option and I cancelled the install. Where did I go wrong?
Thanks

I recommend that you view the files on your windows 8 system to verify that they are good. That will atleast stop the sweating.
A few things could be wrong with the vista system.
1) The correct fonts may not be installed or are corrupted
2) The video card driver needs updating
3) The preference file for illustrator is corrupted try restarting illustrator while holding down ctrl-alt-shift or command-option-shift (former=windows latter=mac)
4) Illustrator needs updating
5) Time to upgrade from Vista (If your system can support it, it may be wise to do so anyway, since MS is not supporting it either)

HD deleted, USB Boot-Stick not working

Hi,
At first I had Snow Leopard 10.6.8.
I prepared a USB Boot-Stick for OS X Yosemite by following the instructions on a website.
I deleted my Harddrive and then tried to install Yosemite from the USB-Stick.
Unfortunately it gives me this error message (I'm german so my translation might not be fully correct):
-     OS X could not be installed on your Computer.
      The process could not be finished. Undefined error: 0
      Close the installation program to restart your Computer and try again.
So now I don't know what to do as I don't have a Snow Leopard Installation CD.
I have a Time Machine backup if that's of any help.
Please help me fix this.

Since you no longer have a Snow Leopard DVD, restore your entire system by following these instructions:
OS X Yosemite: Revert to a previous OS X version
Then, install Yosemite from the App Store.
The instructions you found on a website are probably wrong. If you want to retain the Yosemite installer program for future use, copy the downloaded "Install OS X Yosemite" file prior to the installation. You may then use it to install Yosemite on as many Macs as you wish.

GRUB doesn't detect NTFS partition

I recently installed windows to my second hard disk (/dev/sdb2 or (hd1,msdos2)), but GRUB fails to recognize the NTFS file system on it.
GRUB> ls
(hd0,msdos1) (hd0,msdos2) (hd0,msdos3) (hd0,msdos4) (hd1,msdos1) (hd1,msdos2)
GRUB> ls (hd1,msdos1)
Partition (hd1,msdos1): File system type ext* # etc
GRUB> ls (hd1,msdos2)
Partition (hd1,msdos2): No known file system detected
And yet there is a fully-functioning NTFS file system on this partition. Why do I know this? Because when I boot the entire hard disk from within QEMU, suddenly...
GRUB from within QEMU> ls (hd1,msdos2)
Partition (hd1,msdos2): File system type ntfs # etc
... and windows successfully boots from the disk.
I realise QEMU is not really comparable to BIOS, but I wonder why GRUB fails to recognize this single one NTFS partition, while it does recognize the other ext4 partition... Now, this isn't currently a severe issue, since I'm simply booting the windows partition with QEMU. The main reason I need to boot windows is to run some graphics-heavy programs, and as far as I know, QEMU can't do Direct3D emulation (or hardware acceleration?).
Last edited by DeatzoSeol (2015-05-21 00:20:14)

Hmm, I don't think that could be the cause, I've tried insmod'ing all the necessary deps but to no avail... grub simply doesn't see the ntfs partition...
Relevant menuentry:
menuentry 'Windows 7 (loader) (on /dev/sdb2)' --class windows --class os $menuentry_id_option 'osprober-chain-0530C8122E9BEF62' {
insmod part_msdos
insmod ntfs
insmod chain
insmod ntldr
set root='hd1,msdos2'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd1,msdos3 --hint-efi=hd1,msdos3 --hint-baremetal=ahci1,msdos3 0530C8122E9BEF62
else
search --no-floppy --fs-uuid --set=root 0530C8122E9BEF62
fi
chainloader +1
This was generated with os-prober, so I'm assuming it should work out of the box?

Usb Boot issue - v570

I have deleted the hidden partition as well as the D partition and repartitioned the drive. (200 mb partition left in place)
However it seems that after this the laptop will no longer boot from USB. I have tried several USBs with different linux distributions and methods (unetbootin, image copy) and every time I select USB from the boot menu or put it first in boot order (the drive is recognized - even shows the name), the laptop just skips it and boots Windows anyways. Even the same USB that worked fine before doesn't boot after this partitioning!
Anyone know what could be the problem and how to fix it?
subject edited

hi hydroxide.
have you flashed any bios update? can you try to boot your computer without hdd? ( remove it if you can )

USB boot, detect correct / partition

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