URL: <https://savannah.gnu.org/bugs/?63499>
Summary: multiboot information structure has color_info offset by 2 bytes Project: GNU GRUB Submitter: jasonyoungberg Submitted: Sat 10 Dec 2022 01:19:58 AM UTC Category: Booting Severity: Major Priority: 5 - Normal Item Group: Software Error Status: None Privacy: Public Assigned to: None Originator Name: Originator Email: Open/Closed: Open Release: other Release: Discussion Lock: Any Reproducibility: Every Time Planned Release: None _______________________________________________________ Follow-up Comments: ------------------------------------------------------- Date: Sat 10 Dec 2022 01:19:58 AM UTC By: Jason Youngberg <jasonyoungberg> Inside the multiboot information structure <https://www.gnu.org/software/grub/manual/multiboot/multiboot.html#Boot-information-format>, the color_type color_info <https://www.gnu.org/software/grub/manual/multiboot/multiboot.html#Boot-modules:~:text=color_type%20is%20defined%20as%20follows> bytes seem to be offset by 2 bytes. I would expect values of {16,8,8,8,0,8}, but those bytes are found at 112 (0x70), instead of 110 (0x6E) as stated in the docs. Here is a memory dump of the multiboot information structure: 00010000: 67 12 00 00 7f 02 00 00 80 fb 01 00 ff ff ff e0 00010010: 78 00 01 00 00 00 00 00 00 00 00 00 0a 00 00 00 00010020: 28 00 00 00 34 01 01 00 09 00 00 00 90 00 00 00 00010030: a4 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00010040: 7c 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00010050: 00 00 00 00 00 00 00 00 00 00 00 fd 00 00 00 00 00010060: 60 09 00 00 20 03 00 00 58 02 00 00 18 01 00 00 00010070: 10 08 08 08 00 08 00 00 00 66 89 43 47 52 55 42 I created my iso with the commmand 'grub-mkrescue -o os.iso .tmp' I tested it using 'qemu-system-i386 -cdrom os.iso' This is my multiboot header: .set ALIGN, 1<<0 # align loaded modules on page boundaries .set MEMINFO, 1<<1 # provide memory map .set VIDINFO, 1<<2 # provide video information .set FLAGS, ALIGN | MEMINFO | VIDINFO .set MAGIC, 0x1BADB002 .set CHECKSUM, -(MAGIC + FLAGS) # Multiboot header .section .multiboot .align 4 .long MAGIC .long FLAGS .long CHECKSUM .long 0, 0, 0, 0, 0 .long 0 # Set graphics mode .long 0, 0, 0 # Width, height, depth # ... I'm using grub version 2.06-2, and qemu version 6.2.0. _______________________________________________________ Reply to this item at: <https://savannah.gnu.org/bugs/?63499> _______________________________________________ Message sent via Savannah https://savannah.gnu.org/