Unreadable block in multiblock reading on dd / ddrescue: How does it handle it?

Let's say that I set the block size of dd or ddrescue to 256K. A sector of flash drives usually has 512 bytes, a sector on optical data discs has 2048 bytes. Let's assume that in the next 256 KB, **just one sector is unreadable.** Every other sector is readable. ### What happens to the multiblock transfer? * Does it transfer anything at all? * Does it transfer the readable parts as usual? It would be great if it did transfer **all readable blocks** as usual.