legacy loader error HD / USB not found

[Bugsy]

Hi All,

I'm facing really weird issue. I'm getting messages as:
Starting legacy loader
Using load options 'USB'
Error: Not Found while loading legacy loader

or in case of trying to boot legacy
Starting legacy loader
Using load options 'HD'
Error: Not Found while loading legacy loader

Used to have retina MacBook Pro (mid-2014) now replaced to mid-2015 model and using same USB key which worked perfectly I can't get system discovering this USB key anymore.
In fact what I've found out is that the system can't boot any non-EFI mode, meaning legacy mode doesn't seem to work.

This seems to be completely due to some firmware settings and nothing on the disk.
The system was restored as full disk image (dd) copy from the image taken from old system with all partitions, etc.

The old system was set manually, by enabling Windows via bootcamp, then encrypting with TrueCrypt, etc.

The need to boot from USB is to be able to decrypt the TrueCrypt volume using some dd from grub4dos level.
The boot sequence which worked for me, even without refind was:
"hold option", boot from USB in legacy mode (this was painfully slow, but worked)
USB loaded grub4dos
grub4dos manipulated MBR sectors on internal drive and loaded TrueCrypt ISO to start windows boot process.
Windows loaded

If any of you would know any other solution which would allow "dd" and ISO image boot as grub4dos replacement, that would be great. So far grub2 can't do that.

Any hints on how to get this working would be great. I want to avoid reinstallation of everything from scratch as this might not lead to any solution for that whilst will be painfull and timeconsuming.

The problem will have something to do with NVRAM, I guess.
Trying to bless device to legacy mode, even with CSR disabled I'm getting:

sudo csrutil status
System Integrity Protection status: disabled.

sudo bless --device /disk2s1 1 --setBoot --verbose --legacy
EFI found at IODeviceTree:/efi
Firmware feature mask: 0xFC03FF3F
Firmware features: 0xFC03F536
Legacy mode NOT suppported
Legacy mode not supported on this system

Just to be clear I have Hybrid setup.
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 977105026
Partitions will be aligned on 128-sector boundaries
Total free space is 264385 sectors (129.1 MiB)

Number Start (sector) End (sector) Size Code Name
1 2048 411647 200.0 MiB EF00 EFI System
2 411648 156659711 74.5 GiB 0700 TestDump1
3 156659712 321697791 78.7 GiB 0700 TestDump2
4 321697792 740777983 199.8 GiB 0700 DOS_FAT_32_Untitled_3
5 741040128 742088703 512.0 MiB AF00 Apple HFS/HFS+
6 742088704 801730559 28.4 GiB 8300
7 801730560 975835263 83.0 GiB AF05 Maco
8 975835264 977104799 619.9 MiB AB00 Recovery HD

Command (? for help): r

Recovery/transformation command (? for help): o

Disk size is 977105060 sectors (465.9 GiB)
MBR disk identifier: <hidden>
MBR partitions:</hidden>

Number Boot Start Sector End Sector Status Code
1 1 411647 primary 0xEE
2 * 411648 156659711 primary 0x07
3 156659712 321697791 primary 0x07
4 321697792 740777983 primary 0x07

Interestingly enough, after each restart, the active boot partition gets back to number 4 for unknown reason.

Thanks in advance for help.

[Bugsy]

Further research shows that this might be related to firmware changes in new Macs.
Some articles show that with new Macs, i.e. MacBookPro11,5 with firmware MBP114.0172.B09 it is no longer possible to Bootcamp Windows 7, which has most probably something to do with dropping legacy support (MBR boot), as Windows 8 was the first introducing EFI boot.

There's also thread on this here:
https://discussions.apple.com/message/30499735#30499735
https://forums.kali.org/showthread.php?31275-MacBookPro11-4-and-rEFInd-impossible-to-boot-kali

This leads to the conclusion that unless there is a way to support legacy mode / MBR on new Macs, there's no way to use Windows 7, or any other system which requires MBR.

If this is true, then I'm stuck with my efforts to get TrueCrypt working on these Macs and there's no working replacement supporting EFI boot.