I doubt if it can be called as a loophole. If Windows is downloaded through Upgrade Assistant, then it is installed from ESD via setup. The same setup is used for retail media to install from WIM. Also if memory serves me right, then DISM in Preview can service ESD images too.
Partially Core Single Language is meant for emerging market (similar as Home Basic) & you can't install LP after installing. Besides that it is same as Core. Oh well... you can only get CSL through your OEM.
Think "Windows 8 Starter". It was created to help curb piracy in china etc.etc. and for "a small number of emerging markets".
Whoops!! Its a MAK. Code: Product Key: YNB3T-VHW8P-72P6K-BQHCB-XXXXX Profile: C:\Windows\System32\spp\tokens\pkeyconfig\pkeyconfig.xrm-ms Validity: Valid Product ID: 00138-10010-05253-AA937 Advanced ID: XXXXX-01381-001-005253-03-16393-9200.0000-2112013 Activation ID: ffdd27bd-30ad-4b58-ba24-c7e3b8026443 Edition Type: Professional;ProfessionalN;Enterprise;EnterpriseN Description: Win 8 RC Professional;ProfessionalN;Enterprise;EnterpriseN Volume:MAK Edition ID: [Blue]X18-05628 Key Type: Volume:MAK EULA: Volume Crypto ID: 1381