Create random number is batch file

My aim is to create a random hexadecimal number that looks like 02xxxxxxxxxx with a batch file. But I habe problems by passing the single digit number between different batch files.

top.bat

for /f %%i in ('ran') do set b0=%%i
echo %b0%

ran.bat

@echo off
SET /a A=%RANDOM%*16/32768
for /f %%i in ('tohex.bat A') do set a0=%%i
echo %a0%

tohex.bat

@echo off & setlocal ENABLEEXTENSIONS ENABLEDELAYEDEXPANSION
set LOOKUP=0123456789abcdef &set HEXSTR=&set PREFIX= 
if "%1"=="" echo 0&goto :EOF 
set /a A=%* 
if !A! LSS 0 set /a A=0xfffffff + !A! + 1 & set PREFIX=f 
:loop 
set /a B=!A! %% 16 & set /a A=!A! / 16 
set HEXSTR=!LOOKUP:~%B%,1!%HEXSTR% 
if %A% GTR 0 goto :loop 
echo %PREFIX%%HEXSTR%