Dell PowerEdge R740: EFI+HTTP boot using Grub crashes when the kernel tries to unpack the initramfs

Issue

• When attempting to boot a system using EFI+HTTP protocol (and Grub2 as boot loader), the system panics when the kernel tries to mount the initramfs

  [...]
  Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
  [...]
  Hardware name: Dell Inc. PowerEdge R740/...
  

• Alternatively, a red screen of death can be displayed by the EFI firmware, before the Linux kernel even executed

  PowerEdge R740 - BIOS 2.10.0
  A system restart is required. The system detected an exception during the UEFI pre-boot
  environment. Check serial output or iDRAC debug logs for detailed information.
  -------------------------------------------------------------------------------------
  Type: General Protection Fault (13) Source: Software (UEFI0011) on BSP
  [...]
  LastMsg:
  
  LBRfr2 5132FE5E HttpDxe.efi +012E5E
  [...]
  -->RIP 5131FC77 HttpDxe.efi +002C77
  [...]
  

  Note: addresses may vary.

• Systems from other vendors than Dell can boot without issue using exact same binaries and EFI+HTTP protocol