Default please help me edit bstid file (bluestack 0.8.5)

hi , im using rooted bluestack 0.8.5 .

and i need edit file /proc/bstid to change BS serial .

im tried to edit by using root explore ( i gave rw permission) but it say cant save .

then i try to use adb to write/copy file , but it still say :

Code:
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adb push C:\bstid /proc/
failed to copy 'C:\bstid' to '/proc//bstid': Read-only file system
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adb remount
* daemon not running. starting it now *
* daemon started successfully *
remount succeeded

adb push C:\bstid /proc/
failed to copy 'C:\bstid' to '/proc//bstid': I/O error
Code:
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C:\Users\Judas\Downloads\Compressed\ADB>adb shell
root@vivo:/ # su
su
root@vivo:/ # mount -o rw,remount /proc/bstid /system
mount -o rw,remount /proc/bstid /system
root@vivo:/ # echo "xxxxxxxxxxxxxxxxxxxxxxxx" > /proc/bstid
echo "xxxxxxxxxxxxxxxxxxxxxxxx" > /proc/bstid
but nothing change .

could anyone please help me, how to edit bstid file ?
or please tell me a way to fake bluestack 0.8 serial