Just to complete this thread, here is the final outcome:
Here is a quick Summary for the 6UL boot issue. An errata has been created, the details of which are below. A ROM patch has been identified and validated, the start of this production is set for Sept 22 2017.
The date code will be the only way to differentiate the material, as no other part number or hardware register will be changed.
Errata: ERR11115 ROM: Failures when using a specific boot image start address for SD/eMMC/NAND/SPINOR boot
SW Workaround: For SD/eMMC/NAND/SPINOR boot, set the boot image start address greater or equal to 0x908000.
Fix: There is a ROM patch to fix the issue on i.MX 6UL Rev 1.2. With the patch, the entire OCRAM range can be used (again) starting at 0x907000.
Identification: Devices with the ROM patch will be identified with an effective date code, later than 9/22/2017
Other devices impacted: please look into the errata documents of the respective devices
6SLL
7D