Winboot failed to load WinPE greater than 600MB on Dell R640

[vpnchoudhary]

Hi -

I am getting below error on dell R640. The machine has 170 GB RAM. So memory is not an issue. It appears that on this hardware Wimboot can only work with 1GB of address space.

The exact error is "There isn't enough memory available to create ramdisk device."
Status: 0xc000007

The wimboot info is captured before it hand over control to bootmgr.
https://1drv.ms/u/s!Ag6Nr700xzwc-HrQjwrg...2?e=CeWpWd

The top two screen shoots are from R640. Left hand side is trying to boot from a 650MB winpe whereas right hand side successfully booted from a 580 mb Winpe.
The bottom image is from a different sku of dell server with larger Winpe Image and it worked fine.

My guess based on looking at address space is that for larger winpe, the address space of bootmgr will overlap with the address space where BCD is stored. Hence the error.

R640->ipxe(wimboot)->win image 650MB | bootmgr start at 0x434a0 + wim (28e25c38) = 28E6 90D8 ->BCD starting point (25784074)

R640->ipxe(wimboot)->win image 580MB | bootmgr start at 0x434a0 + wim (243afee8) = 243F 3388 ->BCD starting point (2a23e074)

I can be completely off here but it does appear that Wimboot is not using the ram space effectively.

I am using the latest version of wimboot (2.6.0), I also tried with previous version but same result.

Any pointers on how to fix this issue ?