I'm trying to boot Lubuntu and elementary OS from a USB stick, but the computer stops with the message "you need to load the kernel first." I also see an "invalid magic number" error. Secure Boot is currently disabled, and I've tried both UEFI and Legacy modes. I created the USB using Rufus and have already been troubleshooting this for two days. The laptop has an Intel i3 processor, 8 GB of RAM, and integrated graphics. What should I check or redo?
2 Answers
Start over with the official installation instructions rather than trying to manually load the kernel. For a modern laptop, use UEFI mode instead of Legacy/CSM. Secure Boot can usually remain enabled for distributions that support it, although temporarily disabling it is fine for testing. Also make sure the computer is actually booting from the newly created USB and remove any old or partially written installer before recreating it.
“Invalid magic number” usually points to a corrupted ISO, an incomplete download, or a USB that wasn’t written correctly. Download a fresh ISO from the distribution’s official site and verify its checksum if one is provided. Then recreate the installer from scratch with a current version of Rufus, selecting the correct ISO and using the recommended UEFI/GPT settings. If possible, test with another USB drive too, since faulty media can cause the same error.

Thanks, I’ll download the ISO again and recreate the USB using the UEFI settings in Rufus.