Comment 3 for bug 1806843

I;am sorry i can't understand how it's possible.
I have 1 nvme disk for 500gb with
2 uefi boot sector by 400mb
nvme0n1p4 - fat32 with uefi for ubunru
nvme0n1p2 - was created before my installation with windows MBR.
nvme0n1p6 - ext4 250gb for ubuntu
nvme0n1p3 - ntfs near 240gb that was created with widnows.

So when i start install ubuntu i manually choose nvme0n1p4 as boot place and mount "/" to nvme0n1p6.

Can you explain me where Ubuntu installer try to install grub, and where not enough space?

P.S. i try installation with more then few times and also found one more line in logs.
"efibootmgr не может сделать загрузочную запись: нет такого устройства или адресса".
I use russian language pack.
Bit in english it can be translaate as "efibootmgr can't create boot record: no such device or adress".