XL will not read exfat formated USB  

RE: XL will not read exfat formated USB

Similar discovery. I had a stubby Samsung drive that I thought would be ideal as less chance to bump.... Seems only fat32.

I then reformatted it to fat32 specifically for the XL, it recognised it and I had some success; I'm using Prusa Link/Connect to wirelessly transfer but the results were really erratic so have moved back to a native fat32 usb and resolved.

RE: XL will not read exfat formated USB

That's right - exFAT is not supported. https://help.prusa3d.com/article/sd-cards-and-usb-drives_112291

It would be nice though if the printer would report an error rather than showing and empty drive.

RE: XL will not read exfat formated USB

None of the buddy based printer do. GitHub issue here https://github.com/prusa3d/Prusa-Firmware-Buddy/issues/3011  it seems the devs are using the tiny usb library for usb support. Which does not support exfat. 

RE: XL will not read exfat formated USB

Im no expert...just glancing, but tinyusb does seems to use FatFs as the filesystem module, as does the Buddy code: https://github.com/hathach/tinyusb/blob/master/lib/fatfs/source/ff.c
and
https://github.com/prusa3d/Prusa-Firmware-Buddy/blob/master/src/buddy/filesystem_fatfs.c

FatFs does support exFAT: http://elm-chan.org/fsw/ff/00index_e.html

Its enabled in the config code of the project by setting FF_FS_EXFAT to 1
http://elm-chan.org/fsw/ff/doc/config.html#fs_exfat

Enabling exFAT does seem to require you modify your filename code

RE: XL will not read exfat formated USB

Thank you all! This thread pointed me the right direction solving my problem I described here:
https://forum.prusa3d.com/forum/postid/758874/

I used exFat formatted drive with no issues until the last fw upgrade (6.2.5), then skipped lines problem popped up.

As for the USB formatting:
Format USB drive properly as (and only as!!!) FAT32, Primary partition and set to Active - this condition is often not mentioned! If not set to Primary and Active, you won't see the USB in XL printer (same applies to other Prusa models too). I used MiniTool Partition Free for formatting the USB stick (here you can easily compare the format settings of the original Prusa USB supplied with the printer and your new USB stick).

I think the devil hides in similarity of exFat to the older FAT32. As Neophyl pointed out, devs use libraries which probably conflict in some aspects with exFat newly added features (in relation to FAT32). Deceivingly, exFat (if set Primary and Active) will be recognized by XL printer and may work flawlessly if conditions are right. But it is a problem waiting for it's chance... So, never exFat, only FAT32!