I manage to reuse back my 16gb spare card back to my HD7.My stock card now i'm using for my ext. sd for my Galaxy S3 Thanks to the OP and Magpir for this link.
Firstly I reformat both my Sandisk 16gb to FAT32.My spare card after formatted I slot it into my HD7.(I just use 1 screw only to tight the cover.I didn't put the top cover for the gps.(My bad) I hard reset my device and notice there's a single yellow words and number at the bottom.After the device completed it's stuff it reboot and I receive an error for my sd card Then I remove the sd card and try to reformat again but it doesn't work My pc can't recognise the card
I'm finish.What I do next is I slot it again to my HD7 and assemble back everything.I do hard reset THIS time I notice there's another yellow words and numbers so it makes two. As usual after it complete it's stuff it reboot again same error happens. So I decided to flash RSPL and flash rom and hope it works.I put it into TRI COLOR and RSPL my device, IT WORK ad Iwas quite happy.So I decided to flash rom to my device.GUESS what IT WORK.So I just follow the usual steps on the device.Zune and WMDC works perfectly well. I switch off my device and on again to see whether it still work. I reflash again to Tango 8779 and it still work.
Now my question Is why it work and why it doesn't recognise the rom before it unlock.
NOTE: After unlock the stock card I don't relock and neither do any backup.
This is an update and hope it work for someone.