What were you trying to do that didn't work?

On Dell PoweRedge T360 with attached PERC H355 storage, it's not possible to load the large initramfs-0-rescue rescue file created after installing RHEL8 (128244KiB large).
This occurs because there is not enough contiguous memory to store the initramfs.
The lsefimmap command shows "conv-mem" is limited to a couple of chunks below 4GB:

Chunk #  Type      Physical start  - end             #Pages        Size Attributes
1        conv-mem  0000000000000000-000000000009ffff 000000a0    640KiB UC WC WT WB
2        conv-mem  0000000000100000-000000000b27efff 0000b17f 181756KiB UC WC WT WB   <<< kernel from 0x1000000
3        conv-mem  0000000013600000-0000000019dc9fff 000067ca 106280KiB UC WC WT WB
4        conv-mem  00000000284f0000-00000000284f1fff 00000002      8KiB UC WC WT WB   <<< kernel params + cmdline
5        conv-mem  00000000290ff000-000000002ff3cfff 00006e3e 112888KiB UC WC WT WB

The kernel param structure and cmdline get loaded into chunk 4, whereas the kernel itself gets located into chunk 2, because chunk 2 contains the preferred address (0x1000000).
Unfortunately, this results in chunk 2 remaining memory to be 101247KiB large (0x0b27efff-(0x1000000+0x3f9f000) where 0x3f9f000 is the size of the kernel image).

If Grub was able to put the kernel in chunk 3 or 5, loading the initramfs would be possible.
Currently this is not possible, because if the preferred address is available, it's used, there is no choice.

Please provide the package NVR for which bug is seen:

grub2-efi-x64-2.02-156.el8_10

How reproducible:

Always on customer platform