Hi, > on the V14IIL Lenovo in > all 3 modes- Legacy BIOS,UEFI,and UEFI+secure boot- success rate 100%. > 2. mkusb cloning iso file > 3. rufus in Windows 10 (dd mode)
So now it looks like valid GPT does the trick for Ubuntu ISOs on Lenovo. There remain riddles: Why does the grub-mkrescue ISO not boot on V14IIL ? (I still wonder which other ISOs boot on that machine.) Why did the old Ubuntu ISOs with their invalid GPT boot on sudodus' V130 whereas a similarly invalid GPT did not help with the 20201007.1 ISO ? Maybe Canonical Ltd. should ask Lenovo Group Limited for enlightenment. ------------------------------------------------------------------------- The xorrisofs option to cause GPT during the production of an Ubuntu ISO would be -appended_part_as_gpt With GPT it is crucial for mountability of partition 1 (the ISO) to use option -partition_offset 16 GPT partition 1 may start only after the GPT array. So it cannot start at LBA 0. The best non-0 value for the partition start is ISO LBA 16 (GPT LBA 64). Lower is not possible, higher is waste. ------------------------------------------------------------------------- Valid GPT is fewly tested with popular ISOs. If Ubuntu ISOs switch from MBR partition table to GPT, then it will become interesting to see whether there are any EFIs which hate it (and why they do). Have a nice day :) Thomas -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1886148 Title: failure to boot groovy daily To manage notifications about this bug go to: https://bugs.launchpad.net/oem-priority/+bug/1886148/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs