problem uart bst

i want write super imei on my i9500
all is ok my device rooted..usb debug is on but after this error my phone reset !
Device Info (UART)
Model: GT-I9500
SW Version: I9500XXUFNB3
Customer Code: SER
Unique Number: CV30025FE6549C0
Flash Memory: –
Chipset : true
Key ID : 0833
Time used : 22.0 s

Prepare environment … Device do not have ADB interface, turn on device USB DEBUG and connect with usb cable,then re-scan device
This operation need boot to normal mode
Reboot device to NORMAL mode …
Wait device ready … can’t wait a UART connected device boot ready.

plz help me