During the modding process, bytes are being changed by the tools. We do not know why. Even though the mods are manual, they need to be decompressed and recompressed with tools..Changes happen that may alter function, evidenced by the flash problem. I take it you have tried to flash an unmodded bios before requesting a mod to be sure it works (at least the way you want it to..)?? Are you at all familiar with the mod process being done here??
In regaurds to the F42 bios mod. This mod comes up as ver F.38 when i recheck my bios. Released in Aug. 06. F.42 was released in 3/09. Previous version that I find for my HP DV6200 was F3D released in Nov 07 which was considered critical to fix previous problems. It seems old to put in place of one near three years newer?
A way to add the SLIC. Most of the time, the old slic is changed and a new one is introduced. I found them, and just replaced the old ones in place. Nothing additional done. let 'er rip. It is just a different way of accomplishing the same end. Different methods work better on different boards..