nanobsd boot problem

[Jack Mc Lauren]

Hello friends
Thanks for helping me building a nanobsd image. I did build
an image with no problems ( special thanks to Paul Schenkeveld  ).
But I have some problems in the second phase of running a
device from a nanobsd image. 
After copying the image on a flash memory, and after I set
the system to boot up from flash memory, I just see a black screen and a
blinking cursor ! looks like the boot device ( flash memory ) is not recognized
by the system.
Here are my debugging information , if they are not enough,
tell me please to send you necessary informations :
dmesg output :
da0 at umass-sim0 bus 0 scbus0
target 0 lun 0
da0: <UFD 2.0 Silicon-Power8G
PMAP> Removable Direct Access SCSI-4 device
da0: 40.000MB/s transfers
da0: 7388MB (15130624 512 byte
sectors: 255H 63S/T 941C)   
according to the last line, I change the NANO_SECTS to 63
and NANO_HEADS to 255. (in nanobsd.sh).
ls /dev output :
           da0s1           da0s1a     ad6s1b          da0s3           ad6s1d          da0s4
according to the first column , I set NANO_DRIVE to da0. (in
nanobsd.sh)
and here are the contents of the flash memory :
                ls /mnt
.cshrc          boot            lib             rescue          usr
.profile        cfg             libexec         root            var
.snap           conf            media           sbin
COPYRIGHT       dev             mnt             sys
bin             etc             proc            tmp
Am I missing something ?? could you please me please ?