I’ve been diving into creating a custom ISO for RHEL7, and honestly, I’m hitting a wall with the whole UEFI booting from a USB drive thing. It’s been a bit frustrating, to say the least. I’ve followed a bunch of guides online, but something still seems off, and the system just won’t boot from my USB. Has anyone tackled this before?
Here’s the deal: I’ve got my custom ISO all set up, and I thought I did everything right – used the right tools to create the image and made sure to format the USB properly. I’ve set it up to be UEFI-compatible, but when I try to boot from it, it just skips right past the USB and goes straight to the hard drive.
I’ve tried a couple of different USB drives thinking it might be a hardware issue, and I’ve even made sure that the UEFI settings in BIOS have the USB as the first boot option. I am also aware that there’s a difference between legacy BIOS and UEFI, so I double-checked to make sure everything is in UEFI mode.
I did notice that when I check the content of the USB, it looks alright, but I wonder if there are specific files or settings that I might be missing. I’ve read something about needing to have the right EFI boot files in the right directory structure. Anyone know exactly what should be in there?
And here’s where it gets even trickier. I sometimes manage to get other ISOs to boot just fine from the USB, but it’s just this custom RHEL7 one that’s giving me headaches. Has anyone been in a similar situation, or does anyone have any tips for troubleshooting? Any advice on what I should focus on would be super helpful.
Just to clarify, I’ve also made sure that Secure Boot is disabled, since I’ve heard that can cause issues as well. But I’m still at a loss and could really use some insight from anyone experienced with this! Thanks in advance!
Sounds like you’re in a bit of a tough spot with your custom RHEL7 ISO and USB booting! It’s super easy to miss some small details when diving into UEFI booting.
First off, ensure that your USB drive is formatted as FAT32. UEFI systems usually prefer this format, and while some might work with NTFS, FAT32 is the safest bet. If you haven’t done this yet, you can use tools like GParted or the built-in formatting tools on Windows.
Next, about those EFI boot files. You should have a directory structure like this on your USB:
Make sure that the
bootx64.efifile is in the correct location. If your ISO has a different boot file structure, that might be the issue. Also, if you’re using a tool to create the bootable USB, double-check that it supports UEFI. Some tools work better with specific types of ISOs.You mentioned that other ISOs work. That info tells us your USB and BIOS settings are likely cool. Maybe try using a tool like Rufus for Windows or woeusb for Linux to create the bootable USB from the ISO; it does a good job of setting things up for you automatically.
Since you’ve already checked the BIOS UEFI settings, ensure that you’re also not using a Fast Boot option that could be skipping USB devices. It’s worth a shot to reset BIOS settings to defaults just to be sure.
Oh, and about Secure Boot – good call on disabling that! Some custom ISOs might not have the necessary signing for Secure Boot, and it can definitely cause issues.
Lastly, when troubleshooting, it can be helpful to plug in the USB after BIOS has loaded its settings, as sometimes BIOS can be picky about recognizing USB devices if they’re already plugged in during boot. Good luck, and I hope you get it figured out soon!
Tackling UEFI boot issues with custom ISOs, such as your RHEL7 project, can indeed be frustrating, especially given the intricate nature of boot processes. Since you’ve confirmed that the USB is the first boot option in your UEFI settings and that Secure Boot is disabled, let’s ensure that you have the correct directory structure and files on your USB drive. A typical UEFI bootable USB should have an “EFI” directory at the root level containing the “BOOT” directory with the necessary boot files. For a RHEL7 ISO, you would typically place a file named “BOOTx64.EFI” inside the “EFI/BOOT” directory. This file is crucial as it’s the UEFI bootloader for your operating system. Make sure that all files are copied correctly and that there are no hidden files preventing the boot process from recognizing the USB correctly.
If you’ve verified your directory structure and the necessary files are present, you may want to explore further options. Ensure that the USB drive is formatted to FAT32, as UEFI systems typically require this format to read the boot files. Additionally, using tools like `mkfs.vfat` can be useful to explicitly format the USB in a way that ensures compliance with UEFI specifications. Should issues persist, consider testing the USB on a different system to isolate whether the problem is specific to your hardware. Lastly, reviewing the boot logs, if accessible, on the UEFI firmware may provide clues as to why the USB is being skipped. Sometimes, updating the BIOS can also resolve hidden compatibility issues with UEFI booting. Good luck with your troubleshooting!