Need hdr or rom files for Dell bios

[t4h4]

Hi guys,
I bricked my dell laptop ( Dell inspiron 3721  )
i need how to extract the .hdr and .rom from bios.exe to make a flash bios  recovery ( https://www.dell.com/support/home/us/en/...erid=70h05 )
i tried the -writehdrfile and -writeromfile but didnt work
can someone guide me please how to do this? 
thank you in advance !

[DeathBringer]

Use WinRAR or 7-Zip to unpack it.

[t4h4]

Use WinRAR or 7-Zip to unpack it.

I did but there s no .hdr or .rom files

[DeathBringer]

It's Insyde BIOS. It has isflash.bin.