Twice now pacman has warned of slow download speed, has then shortened the file, then later modified the package anyway, which seems incorrect.
Here's one of the upgrade screencaps :
"
# pacman -Syu
:: Synchronizing package databases...
system is up to date
world is up to date
galaxy 852.6 KiB 523 KiB/s 00:02 [######################] 100%
lib32 is up to date
extra 7.7 MiB 625 KiB/s 00:13 [######################] 100%
multilib is up to date
universe is up to date
:: Starting full system upgrade...
warning: rsync-openrc: local (20210505-2) is newer than world (20210502-1)
resolving dependencies...
looking for conflicting packages...
Packages (1) firefox-136.0.3-1
Total Download Size: 72.77 MiB
Total Installed Size: 251.43 MiB
Net Upgrade Size: 0.01 MiB
:: Proceed with installation? [Y/n] Y
:: Retrieving packages...
firefox-136.0.3-... 35.0 MiB 118 KiB/s 05:05 [######################] 100%
error: failed retrieving file 'firefox-136.0.3-1-x86_64.pkg.tar.zst' from mirrors.dotsrc.org : Operation too slow. Less than 1 bytes/sec transferred the last 10 seconds
error: failed retrieving file 'firefox-136.0.3-1-x86_64.pkg.tar.zst' from mirror.clarkson.edu : HTTP server does not seem to support byte ranges. Cannot resume.
(1/1) checking keys in keyring [######################] 100%
(1/1) checking package integrity [######################] 100%
(1/1) loading package files [######################] 100%
(1/1) checking for file conflicts [######################] 100%
(1/1) checking available disk space [######################] 100%
:: Processing package changes...
(1/1) upgrading firefox [######################] 100%
:: Running post-transaction hooks...
(1/2) Updating icon theme caches...
(2/2) Updating the desktop file MIME type cache...
"
*
Thanks for analyzing this occurrence in advance -- - -
I'd check mirrorlist. Maybe use rankmirrors.