I am using diskless boot Windows 7 with iPXE. PC is intended to boot from vhdx, which i obtained by snapshotting sata(ahci) hard drive with sysiternals disk2vhd utility. Hard drive was previously in this machine, and it actually boots Windows 7 good. Also i had manipulated vhd a bit, like shrinking volume size on my demands, making boot partition active(its mbr). Then this vhd is shared over network via iSCSI means of windows server os and iPXE bootloader (software solution); I somehow managed to configure it, and it seems to work good.
And windows boot loader is now getting 0xc0000225 error, as it likes to do in various migration processes (ms likes to complicate things)
Here is an answer, a hint to rebuild boot bcd. So i should run
bootrec /rebuildbcd from diskless client PC. In a disk-PC enviroment i could simply put Windows installation USB and run command line in a preboot enviroment. But now i should boot from scsi attached target and to fix it, and it is network boot! So i cant boot usb. I cant even imagine how could i launch windows installation process under such circumstances! How could i get to recovery environment command line? How could i install fresh windows on it?