p4trykx wrote:I was wondering if there is a fast way to check a SD card for badblock
I don't believe that a reliable method exists at all (not even slow one).
The reason is that SD cards map (and mask) internal memory array to the outside world.
The prices of SD cards are so low, that there is no room to throw away anything... SD cards have slightly more physical memory blocks and if some of them are bad, they are substituted with ones from the spare blocks pool... and you purchase a 100% error-free SD card. (This is not unique to SD cards, it was initially used in hard disks)
The price war is so "bloody" that if a SD card has more bad blocks then available spares, it is "downgraded" to lower capacity.
So, the extreme example would be that you buy 4GB SD card which is actually 8GB card but has 1GB bad (physical) blocks.
All this handling is performed by internal controller inside SD card, which does the masquerade to the outside world... Consequently, various test tools are unable to give real information about the SD cards.
Best wishes, Ivan Zilic.