It didn't work for me the first time because I already had a leJOS version running on the card previously.
It appears that you must reformat (FAT32) first, then upgrade. If you don't reformat, the LeJOS bootup looks like it is working, but then stops after awhile.
To format, I used "SD Formatter 4.0 for SD/SDHC/SDXC" from SDCard.org https://www.sdcard.org/downloads/formatter_4/
Supports both windows and mac.