See if there's an actions tab generated by a right mouse click on the usb icon. If there is, click on it, select read/write.
My thumbdrive was detected just fine (as usb1) and I can read all the files on it (it's a FAT32 format with a bunch of windows files on it) but I cannot WRITE anything to it. I've gone to permissions and granted anyone and everyone full permissions and still no love. I've also unchecked 'read only', which also did nothing at all.
Anyone have a hint for me? Keep in mind that I know a LITTLE Linux, but not a lot about hardware.
See if there's an actions tab generated by a right mouse click on the usb icon. If there is, click on it, select read/write.

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