--- preparation of the installation flash drive - with extra checksum check after write and unplug/plug renergy /home/adam/distros/ubuntu # dd if=ubuntu-25.04-desktop-amd64.iso of=/dev/sda obs=64k oflag=nocache status=progress 6278086656 bytes (6.3 GB, 5.8 GiB) copied, 413 s, 15.2 MB/s 12262736+0 records in 95802+1 records out 6278520832 bytes (6.3 GB, 5.8 GiB) copied, 413.856 s, 15.2 MB/s renergy /home/adam/distros/ubuntu # more sum b87366b62eddfbecb60e681ba83299c61884a0d97569abe797695c8861f5dea4 - renergy /home/adam/distros/ubuntu # dd if=/dev/sda count=12262736 | sha256sum -c sum 12262736+0 records in 12262736+0 records out 6278520832 bytes (6.3 GB, 5.8 GiB) copied, 192.864 s, 32.6 MB/s -: OK renergy /home/adam/distros/ubuntu # fdisk -l /dev/sda GPT PMBR size mismatch (12262735 != 31227903) will be corrected by write. The backup GPT table is not on the end of the device. Disk /dev/sda: 14.89 GiB, 15988686848 bytes, 31227904 sectors Disk model: DT R500 Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: gpt Disk identifier: D18ABFB2-FF4D-49E5-9075-9C1556AA882C Device Start End Sectors Size Type /dev/sda1 64 12251911 12251848 5.8G Microsoft basic data /dev/sda2 12251912 12262071 10160 5M EFI System /dev/sda3 12262072 12262671 600 300K Microsoft basic data --- now reboot to that flash drive, let it boot "Enter" on "Try or install ubuntu", then stop the installation on the first dialog (language selection), this is the result: --- extra partition silently created on the rest of installation flashdrive during the first boot --- checksum of the beginning changed (due to change in partition table) --- installation logs on that partition renergy /home/adam # fdisk -l /dev/sda Disk /dev/sda: 14.89 GiB, 15988686848 bytes, 31227904 sectors Disk model: DT R500 Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: gpt Disk identifier: D18ABFB2-FF4D-49E5-9075-9C1556AA882C Device Start End Sectors Size Type /dev/sda1 64 12251911 12251848 5.8G Microsoft basic data /dev/sda2 12251912 12262071 10160 5M EFI System /dev/sda3 12262072 12262671 600 300K Microsoft basic data /dev/sda4 12263424 31225855 18962432 9G Linux filesystem renergy /home/adam # dd if=/dev/sda count=12262736 | sha256sum 12262736+0 records in 12262736+0 records out 6278520832 bytes (6.3 GB, 5.8 GiB) copied, 190.445 s, 33.0 MB/s c59b3d4cfff87356fd71d6cda24a91e1cdbcbbc8d1699036e6e04c8bc493d6bf - renergy /home/adam # mount /dev/sda4 /mnt/a -t ext4 renergy /home/adam # ls -lR /mnt/a /mnt/a: total 20 drwxr-xr-x 4 root root 4096 Apr 19 16:04 install-logs-2025-04-19.0 drwx------ 2 root root 16384 Apr 19 16:04 lost+found /mnt/a/install-logs-2025-04-19.0: total 8 drwxr-xr-x 2 root root 4096 Apr 19 16:04 crash drwxrwxr-x 8 root messagebus 4096 Apr 19 16:06 log /mnt/a/install-logs-2025-04-19.0/crash: total 0 -rw-r--r-- 1 root root 0 Apr 19 16:04 kdump_lock /mnt/a/install-logs-2025-04-19.0/log: total 784 -rw-r----- 1 root adm 0 Apr 19 16:06 apport.log -rw-r----- 1 messagebus adm 7991 Apr 19 16:07 auth.log -rw------- 1 root root 13810 Apr 19 16:06 boot.log -rw-r--r-- 1 root root 2656 Apr 19 16:04 casper.log -rw-r----- 1 messagebus adm 77048 Apr 19 16:06 cloud-init.log -rw-r--r-- 1 root root 3386 Apr 19 16:06 cloud-init-output.log drwxr-x--- 2 root lp 4096 Apr 19 16:06 cups -rw-r----- 1 root adm 101408 Apr 19 16:06 dmesg drwx--x--x 2 root 121 4096 Apr 19 16:06 gdm3 -rw-r--r-- 1 root root 47255 Apr 19 16:06 gpu-manager.log drwxrwx--- 3 root adm 4096 Apr 19 16:06 installer -rw-r----- 1 messagebus adm 128775 Apr 19 16:07 kern.log drwx------ 2 root root 4096 Apr 19 16:04 private lrwxrwxrwx 1 root root 39 Apr 19 16:04 README -> ../../usr/share/doc/systemd/README.logs -rw-r----- 1 messagebus adm 383482 Apr 19 16:07 syslog drwxr-xr-x 2 root root 4096 Apr 19 16:05 sysstat drwxr-xr-x 2 root root 4096 Apr 19 16:06 unattended-upgrades /mnt/a/install-logs-2025-04-19.0/log/cups: total 4 -rw-r----- 1 root adm 759 Apr 19 16:07 access_log /mnt/a/install-logs-2025-04-19.0/log/gdm3: total 0 /mnt/a/install-logs-2025-04-19.0/log/installer: total 104 drwxr-xr-x 2 root root 4096 Apr 19 16:07 block lrwxrwxrwx 1 root root 31 Apr 19 16:06 subiquity-server-debug.log -> subiquity-server-debug.log.4481 -rw------- 1 root root 82060 Apr 19 16:07 subiquity-server-debug.log.4481 lrwxrwxrwx 1 root root 30 Apr 19 16:06 subiquity-server-info.log -> subiquity-server-info.log.4481 -rw------- 1 root root 3926 Apr 19 16:07 subiquity-server-info.log.4481 -rw-rw-r-- 1 adam adam 77 Apr 19 16:06 telemetry lrwxrwxrwx 1 adam adam 44 Apr 19 16:06 ubuntu_bootstrap.log -> /var/log/installer/ubuntu_bootstrap.log.3953 -rw-rw-r-- 1 adam adam 4291 Apr 19 16:06 ubuntu_bootstrap.log.3953 /mnt/a/install-logs-2025-04-19.0/log/installer/block: total 144 -rw-r--r-- 1 root root 48301 Apr 19 16:07 discover.log -rw-r--r-- 1 root root 94867 Apr 19 16:07 probe-data.json /mnt/a/install-logs-2025-04-19.0/log/private: total 0 /mnt/a/install-logs-2025-04-19.0/log/sysstat: total 4 -rw-r--r-- 1 root root 1160 Apr 19 16:05 sa19 /mnt/a/install-logs-2025-04-19.0/log/unattended-upgrades: total 0 -rw-r--r-- 1 root root 0 Apr 19 16:06 unattended-upgrades-shutdown.log /mnt/a/lost+found: total 0