[REQUEST] Panasonic CF-19 MK4 Custom BIOS for 16GB RAM

[CF19ByteBuster]

Hey folks,
Working with a Panasonic Toughbook CF-19 MK4 (i5-540UM, QM57 chipset, Phoenix BIOS). It’s capped at 8GB DDR3 (2x4GB, 1066MHz), but my workload maxes it out. Aiming to push it to 16GB (2x8GB). Later CF-19 models (MK6+) handle 16GB with BIOS tweaks, so I’m hoping the MK4’s QM57 might have hidden capacity unlockable via a custom BIOS.
Anyone modded an MK4 BIOS to bypass the 8GB limit? Looking for a file or guidance—tools used (Phoenix BIOS Editor?), stability results, etc. I’ll test 2x8GB soon to see if the stock BIOS recognizes more, but I’d prefer a confirmed mod first. Can dump my BIOS with a CH341A if needed—just point me to the best method.
Specs:

• Model: CF-19 MK4
  
• CPU: Intel Core i5-540UM
  
• Chipset: Intel QM57
  
• Current RAM: 8GB (2x4GB DDR3)
  
• Target: 16GB (2x8GB DDR3)
  
  

Thanks for any help! Will report back if I crack it.
Cheers,

CF19ByteBuster