I bought a couple of ‘generic’ micro SD cards on eBay about a year ago. They were not much cheaper than brand name cards, and though only speed 6 rated, were available locally for quick delivery. I have a vague recollection that it might have been a RPi product supplied with NOOBS on it (I have a couple of SD adapters with the RPi logo on them).
These were both used in RPi B systems and worked without fault for the last year, though they are not running full time (perhaps a couple of hundred hours of use).
During a Raspbian sofware update, both cards failed with the same problem, they effectively became read-only cards.
I have seen this effect described for SD cards, and more commonly micro SD cards, but not yet experienced it… and interestingly two no-name cards with almost identical usage history seemingly triggered by the same IO intensive software upgrade.
Could it be a fault in Raspbian? Well both cards were copied to Sandisk and Kinston cards, and are working fine… Raspbian is not an install killer of the cards.
I normally buy brand name cards (eg Sandisk, Toshiba, Kingston), though of course with Chinese counterfeiters one never really knows the origin of products.
I won’t be trying these again, the money saved hardly compares with the time spent in diagnosis and recovery.