iPXE EFI - no network after the DHCP sequence

[cbn38]

Finally, after several tests, we noticed the EFI driver 80861523.efidrv (for i350 backplane) works only 50% of the time. We followed your advises in removing the PowerVille/I350 Gbe EFI PXE driver to avoid conflicts.

We noticed various errors when that doesn't work:
- sometimes we observe the same behavior than the snp.efidrv: DHCP seems to work fine, but the network stack remains unusable (20%).
- the firmware freezes while loading the iPXE driver, which is loaded at the end, just before to go in the EFI shell (30%).
- the firmware freezes when iPXE tries to "initializes the devices" (40%).
- sometimes we get an iPXE error: http://ipxe.org/err/2a6540 which points to drivers/net/intel.c (10%)

The EFI application works fine when we launch it from the ESP, and also when we chainload it from PXE. One time (on 30 tests), we got a freeze of our firmware just after iPXE was downloaded from PXE (DXE_ASSERT...).

Please let me know what traces might help to debug.
Thank you in advance for any help.