ArchLinux: Cannot download any package on Raspberry Pi

Many of you out there must have encountered this weird problem - cannot download or synchronize or update AUR database. Pinging any website shows success but whenever you run pacman -Syyy or pacman -Su the following errors occur.

:: Retrieving packages ...
error: failed retrieving file 'fltk-1.3.2-5-armv6h.pkg.tar.xz' from us.mirror.archlinuxarm.org : Operation too slow. Less than 1 bytes/sec transferred the last 10 seconds
warning: failed to retrieve some files
error: failed retrieving file 'libfontenc-1.1.2-1-armv6h.pkg.tar.xz' from us.mirror.archlinuxarm.org : Operation too slow. Less than 1 bytes/sec transferred the last 10 seconds
warning: failed to retrieve some files
error: failed retrieving file 'fontsproto-2.1.3-1-any.pkg.tar.xz' from us.mirror.archlinuxarm.org : Operation too slow. Less than 1 bytes/sec transferred the last 10 seconds
warning: failed to retrieve some files
error: failed retrieving file 'libxfont-1.5.0-1-armv6h.pkg.tar.xz' from us.mirror.archlinuxarm.org : Operation too slow. Less than 1 bytes/sec transferred the last 10 seconds

So, what could be the problem? After scrumming around I found out that the problem was with MTU of ethernet device. I manually set this to 1400, and then it works like a charm. Do this from Raspberry Pi shell.

ifconfig eth0 mtu 1400

The changes will take effect instantly. Then hit pacman -Syyy and the packages will start downloading without further hastle.

[root@archpi sync]# pacman -Syyy      
:: Synchronizing package databases...
core                159.9 KiB  63.9K/s 00:03 [###########] 100%
extra                 2.3 MiB  62.2K/s 00:37 [###############] 100%
community             2.4 MiB  62.3K/s 00:39 [###############] 100%
alarm                27.9 KiB  69.5K/s 00:00 [###############] 100%
aur                  67.9 KiB  67.7K/s 00:01 [###############] 100%

Fun isn’t it?