Every attempt after the first fails on the open rather than on a checksum: pacstrap runs with --noconfirm, so pacman answers yes to "delete it?" and unlinks the package through the bind mount that makes the ISO's offline mirror the target's package cache. The failure screen then carried no diagnosis at all, because the only line it matched -- "is corrupted" under the target cache -- was written by the attempt that already scrolled away. A retry is the state most people are in by the time they read the screen, and it was the one case with nothing on it.
pacman names the repository it read from in that error, not the cache it writes to, so the match keys on the mirror path rather than the target cache path. Where a log holds both attempts the checksum failure still wins: it is the one that names the cause, and the open failures after it are its wake.
The verdict sends the reader to reboot instead of offering a remedy for the medium. Nothing can be weighed once the bytes are gone, and the deletion landed in the live session's RAM overlay rather than on the stick, so a reboot brings the ISO's copy back and the first error after it is the one that says what actually failed.
Omarchybot
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