Seems I was overcomplicating this. For the NIC drivers I did the following: 1. I extracted the LAN Driverpack 2. I added the INf files to the I386\INF folder 3. I added the SYS files to the I386\System32\Drivers folder 4. I added all other misc files to the root of System 32. For the MassStorage drivers I did the following: 1. I extracted the MassStorage Driverpack 2. I flattened the folder structure to have one folder for each driverset. If a folder was named 3, and had 3 subfolders, I just made 3 folders called 31, 32, and 33, and placed each driverset within. 3. Once finished I copied the entire folder into I386\System32 folder 4. I edited the winpeoem.sif to have the following lines: [OemDriverParams] OemDriverRoot=MassStorage OemDriverDirs=31, 32, 33, A1, A2, A3, A4, A5, A6, A7, A8, AD1, AD2, AD3, AD4, AD5, AD6, AD7, AD8, AD9, ADA, AM, AR, AT, AU1, AU2, AU3, AU4, D, H1, H2, H3, H4, H5, I1, I2, IN1, IN2, IT, L1, L2, L3, L4, N4A, N4AR, N4I, N4IR, N123, P1, P2, P3, P4, P5, P6, P7, P8, Q1, Q2, Q3, Q4, S1, S2, S3, S4, S5, S5, S6, S7, S8, S9, SA, SB, SC, SI1, SI2, SI3, V1, V2, VM Everything seems to be working well now...