How to Install the windows 8.1 preview if your Default UI Language is set to en-GB

The working solution. I will not go into very detail because it is risky.
1. remove the cab only IF you installed it before

DISM.exe /Online /Remove-Package /PackagePath:c:\path\Windows8-RT-KB2849636-arm.cab

2. restart
3. Install the English(US) language pack
4. restart
5. change the default UI language in registry

HKLM\System\CurrentControlSet\Control\Nls\Language\InstallLanguage to 0409

6. restart 7. remove the English (UK) language using lpksetup.exe 8. restart 9. Now you have English US Default UI without any other Language Pack installed.
Verify it by starting. DISM /online /get-intl
( Default System UI Language : en-US )
9. be sure that you have 10Gb free disk space
10. From this point you can install the Windows8-RT-KB2849636-arm.msu

Credit to Zomby-1