The problem with fake/china hacked flash drives is that they really use small capacity memory chips and change the drive to look like if the capacity is bigger.
A little bit like if you pick a 128 MB memory chip and put inside an hacked device that re-uses that chip over and over again to "make believe" that the total capacity is, for instance, 8GB.
When the user is writting more than the true capacity, the drive will "loop" to re-write the chip, meaning that if you try to write 1GB of data on a faked 8GB pen drive and the true memory chip is only 128MB, you will end up only with 128MB of data.
You can't turn a fake 8GB pen intro a true 8GB pen with software at all, because you can't store more data then the true memory chip can hold. What you can do is in some cases by the use of vendor-specific software to re-use a fake pen drive by forcing it to re-set to the true capacity. If the pen drive have a 128MB chip and it's advertised/faked to look like 8GB, you can't have a "restore" to 8GB but in certain cases you can have it back as a 128MB.
Of course that it's not advisable. You should just get a new not-faked pen drive, because people who do those fake/hacked drives will use the cheap memory chip/components that they can, and that can mean defective memory chips or over-used (remember that with flash you will have a limit of writes).
If you want to check the true capacity of a pen drive and to test it to verify the true amount of data it can hold, and if the data got damaged or not on the process, use the tool h2testw.
To restore a fake pen drive to the original size you will have to identify the components of the pen and use specific tool for those controllers.

The problem with fake/china hacked flash drives is that they really use small capacity memory chips and change the drive to look like if the capacity is bigger.
A little bit like if you pick a 128 MB memory chip and put inside an hacked device that re-uses that chip over and over again to "make believe" that the total capacity is, for instance, 8GB.
When the user is writting more than the true capacity, the drive will "loop" to re-write the chip, meaning that if you try to write 1GB of data on a faked 8GB pen drive and the true memory chip is only 128MB, you will end up only with 128MB of data.
You can't turn a fake 8GB pen intro a true 8GB pen with software at all, because you can't store more data then the true memory chip can hold. What you can do is in some cases by the use of vendor-specific software to re-use a fake pen drive by forcing it to re-set to the true capacity. If the pen drive have a 128MB chip and it's advertised/faked to look like 8GB, you can't have a "restore" to 8GB but in certain cases you can have it back as a 128MB.
Of course that it's not advisable. You should just get a new not-faked pen drive, because people who do those fake/hacked drives will use the cheap memory chip/components that they can, and that can mean defective memory chips or over-used (remember that with flash you will have a limit of writes).
If you want to check the true capacity of a pen drive and to test it to verify the true amount of data it can hold, and if the data got damaged or not on the process, use the tool h2testw.
To restore a fake pen drive to the original size you will have to identify the components of the pen and use specific tool for those controllers.

"The problem with fake/china hacked flash drives is that they really use small capacity memory chips and change the drive to look like if the capacity is bigger."
Not always......, massive quantities are semi-defective genuine silicon, complete with original manufacturers markings.



And if you want to know where the 'criminals' hang out........

http://bbs.mydigit.cn/read.php?tid=44466

<edit> oh and i forgot this ..........
http://bbs.mydigit.cn/read.php?tid=959



This is WHY they like the "chipsbank" and MXTronics controllers so much, because a little birdy tells me that both have been "tagged" by certain manufacturers for allowing situations where the Nand-Flash chips can be taken out of spec via custom code in the controllers, unfortunately the info is covered by an NDA , but it makes interesting reading.

Bottom line:

1. Do not buy cheap USB stick devices even if they are branded.
2. Don't buy this stuff from a China supplier unless it is well known (Nettec)

As for finding out the "true" size , this can only be provided by the Nand-Flash ID data , coupled with the manufacturers Bad Block Maps.

I have some interesting cases of 16GB chips, that will test fine at 16GB, but actually loose data after 3 days
these are raw chips, not interrogated via controllers.

Then there are the real interesting cases of semi-OTP parts!!! , they will program ONCE from fresh, but any re-write will corrupt random data. (again this is covered by an NDA, but i have seen copies floating on the internet)