установите gcc4.9 на Ubuntu14.04LTS с “ошибкой” несоответствия суммы хеша

Я пытаюсь установить gcc4.9 на Ubuntu 14.04 и работать:

sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt-get update

со следующей ошибкой:

...
W: Failed to fetch http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu/dists/trusty/main/binary-amd64/Packages  Hash Sum mismatch
E: Some index files failed to download. They have been ignored, or old  ones used instead

Я ввожу http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu/dists/trusty/main/binary-amd64/Packages в браузер, ' не находимый' ответ.

попытайтесь установить больше:

sudo apt-get install gcc-4.9

со следующим:

Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 gcc-4.9:i386 : Depends: cpp-4.9:i386 (= 4.9.4-2ubuntu1~14.04.1) but it is not going to be installed
                Depends: gcc-4.9-base:i386 (= 4.9.4-2ubuntu1~14.04.1) but it is not going to be installed
                Depends: binutils:i386 (>= 2.24) but it is not going to be installed
                Depends: libgcc-4.9-dev:i386 (= 4.9.4-2ubuntu1~14.04.1) but it is not going to be installed
                Depends: libc6:i386 (>= 2.11) but it is not going to be installed
                Depends: libcloog-isl4:i386 (>= 0.17) but it is not going to be installed
                Depends: libgmp10:i386 but it is not installable
                Depends: libisl15:i386 (>= 0.15) but it is not going to be installed
                Depends: libmpc3:i386 but it is not installable
                Depends: libmpfr4:i386 (>= 3.1.3) but it is not going to be installed
                Depends: zlib1g:i386 (>= 1:1.1.4) but it is not installable
                Recommends: libc6-dev:i386 (>= 2.13-0ubuntu6) but it is not going to be installed

Проблема, загружающая пакеты, перечисляет из-за "Ошибки" несоответствия суммы хеша - это не работает мне.

Любые предложения будут большими к me:-),