"Hash Sum mismatch" during apt install on Raspberry Pi OS: stale index or out-of-sync mirror?
On Raspberry Pi OS (Debian-based, bookworm assumed), an apt install or full-upgrade can fail with a Hash Sum mismatch error when the local package index under /var/lib/apt/lists no longer matches the repository's current Release and Packages metadata. The apt toolchain only refreshes this index when apt update runs; it does not check freshness automatically
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