CDJ2000nxs won't go into Firmware mode and usb load issues

i'm having 2 issues with my CDJ2000nxs

1) one of them updated just fine. the other however will not load go into the firmware update mode. trying to update from v1.43 to v1.44

2) the second issue is that it will not read certain thumb drives. it seems to be a windows vs mac issue. My husband's thumb drives load fine and he uses a mac. I use a PC. i have a 256gb samsung thumb drive. formatted as fat32 with a 3rd party software because i know that Windows alone will not format thumb drives larger that 32BG. when i use a 32gb drive and format it on the PC it will load. but it will not read the larger thumb drive. i'm guessing this might have to do with the formatting software. but its strange because these 256gb thumb drives work fine with the Pioneer xdj-rx. but it won't load on the 2000NXS.

any and all help regarding this would be greatly appreciated!