More information needed.
What devices are you using or considering to use?
What problem(s) actually occurred?
If the thumb drive has a physical write protection switch the SD Card Reader will not be able to write to the thumb drive.
Barring a defective thumb drive switch perhaps.
And, what ever the circumstances, going "cheap" on the SD Card Reader is not likely to solve the problem.
More likely to fail and not even be able read.....