Bless A Usb For Legacy Boothbay
Bless A Usb For Legacy Booth

Legacy BIOS Access Range Limitation

I followed your directions exactly and installed Clover on both a USB stick and an internal Fat32 formatted drives. Each time, your Legacy installer confirmed a successful installation. However I was never able to boot from either drive into Clover, no matter what I tried in settings. I have been unable to boot using a USB or CD. I have tried enabling Legacy Boot Sources, but it will not enable even after disabling Secure Boot. The funny thing I see is that the boot order option is under storage to enable Legacy, and the option to disable secure boot is under Security. I need an option to boot either from USB or CD. EDIT: I was able to sort of get results using the bless command in Terminal. Specifically, I used. Sudo bless -mount '/Volumes/WDOMedia32/' -legacy -setBoot -nextonly. And then did a restart. Boot was slower, but then I was presented with the normal log-in screen. Installation on a Hard Drive partition for the Legacy system. This method will work on both Legacy systems. First, you have to create a bootable USB drive. I would recommend a USB drive of 4 GB. To create bootable USB I am using Rufus you can download it from here. Step 1: Create a bootable USB drive. Plug USB drive into the computer and open. Legacy Boot Mode. With newer Windows 8 PCs that are designed with UEFI support, the BIOS or firmware often has an option that specifies if the computer can boot into regular operating systems and recovery tools, or if it can boot exclusively into newer UEFI operating systems and environments.

Bless A Usb For Legacy Boothbay

Background

There is an access limitation in some Legacy BIOS of some vendors. For example, some Legacy BIOS can't read the disk beyond 137GB. If you search 'Legacy BIOS 137GB' in the internet, you will get many informations about that.
So if that's the case with the BIOS in your machine and you install Ventoy into a USB drive with large capacity(e.g. 256GB), you will run into problem when booting.

Typical behavior

Bless A Usb For Legacy Booth

1. This problem is Legacy BIOS only, UEFI is OK.
2. Directly dropped into a grub shell when boot Ventoy
3. Works fine with a small USB drive(e.g. 32GB)

Why no problem with other tools (e.g. Rufus)

When you make a bootable USB with other tools like Rufus, the USB drive will be reformatted and all the data in the ISO will be written into the USB from the begginning.
So normally these data will not exceed the BIOS limitation and there is no need to read data from where is out of the range during boot.
But with Ventoy, as mentioned in Disk Layout, the 2nd partition is at the bottom of the USB disk. So it need to read data out of the Legacy BIOS limitation immediately after boot.

Workaround 1

Reformat the 1st partition manually (NTFS/exFAT ...)

To make sure that the file in step 2 will be saved within the BIOS access range.

Copy ventoy.disk.img.xz to the 1st partition

Get ventoy.disk.img.xz from the install package (under ventoy directory). Create a ventoy directory in the 1st partition and copy ventoy.disk.img.xz into it.
That's /ventoy/ventoy.disk.img.xz in the 1st partition.

Notes

It should be noted that, this is just a workaround. There is no software solution for the BIOS limitation. If all the ISO files are within the valid range, there will be no problem. But if you put many many ISO files to the USB disk and some of them will be out of the range. For these ISO files, BIOS can't read them and there will definitely be problems when boot them.
Extra benefits
Just for Legacy BIOS mode, although workaround 1 is used for the limitation of the BIOS, but it can also be used to avoid the situation where the data of the 2nd partition is damaged. Because the workaround proces is to get data from the file mentioned above when failed to access the 2nd partition. The access failure may be due to the limitation of the BIOS, or the file may be damaged.

Workaround 2

Since Ventoy-1.0.14, you can preserve some space at the bottom of the disk. We can make use of this feature, to preserve some space at the bottom of the disk and to 'extrusion' Ventoy's part1 and part2 within the BIOS's access range. Take a 256GB USB drive for example, if the BIOS access limitation is 137GB, we can preserve 150GB space when install Ventoy. So the part1 and part2 of Ventoy will be at the first 106GB space and will not trigger the BIOS's limitation. Please refer Notes for detailed information of the feature.

NapoleonWils0n

Well-Known Member

Reaction score: 143
Messages: 275

A normal freebsd install on mac hardware uses legacy boot so it takes 30 seconds for the boot screen to appear,
we can bless the efi partition and reduce the start up time to a couple of seconds
Preperation
1 - plug in a usb drive to your mac and then run the mac installer and select your external usb drive to install mac on to
2 - after the install has finished shutdown the mac and press option while you start up and select mac osx on the external drive
3 - after you have booted into mac on the external drive use disk utility to erase the internal drive on the mac which we will use to install freebsd onto
Then shutdown the mac and unplug the external usb drive with mac osx on
Freebsd install
1 - plug in a usb disk drive into the mac and insert the freebsd install cd ( that you created )
2 - hold down option as you start up the mac and you will see 2 disc icons, select the icon that says efi
3 - run the freebsd installer and select encrypted zfs on root
Mac disable sips
After the freebsd install has finished shutdown the mac
1 - plug in the external usb drive with mac osx
2 - hold down option and press the power button then select the recovery partition to boot into recovery mode
3 - after you have booted into recovery mode on the external drive open the utilities menu at the top of the screen and select terminal
4 - disable sips on the mac so we can use the bless command to bless the efi partion
+++
5 - quit the terminal to return to the main recovery mode screen
6 - then select shutdown to shutdown the mac
Mac bless efi partition
Next we need to boot back into mac osx on the external usb drive and bless the efi partition
1 - hold down option and turn on the mac and select mac osx on the external drive
2 - open the terminal on the mac and then run the following command to list disk paritions

Look for the efi parition in the list in the terminal it should be /dev/disk0s1
3 - switch to root by running sudo su

4 - create a mount point called ESP in /Volumes

5 - mount the efi partition you found by running diskutil list, it will have efi next to the drive

6 - bless the freebsd efi file

7 - unmount the /Volume/ESP and the mounted freebsd efi partition

8 - exit root

Shutdown the mac and unplug the external usb drive
Freebsd efi boot
now press the power button on the mac and it will boot into freebsd in efi mode straight away instead of using legacy boot
and taking 30 second to boot up