[U-Boot] erasing u-boot from u-boot

[Mike.Worster at Emerson.com]

I'm working with a 2015.04 version of U-Boot, I have it flashed on a i.MX6 DualLite based device in eMMC. I'm now trying to blow away that version of U-Boot from within U-Boot itself (so the device goes back into Serial Download mode).

I've tried erasing the mmc0 (eMMC), the command works, but for some reason every time I power cycle the device U-Boot is still present. How do I delete it?

=> mmc info
Device: FSL_SDHC
Manufacturer ID: 1e
OEM: 1ff
Name: TSEMM
Tran Speed: 52000000
Rd Block Len: 512
MMC version 4.5
High Capacity: Yes
Capacity: 3.5 GiB
Bus Width: 8-bit
Erase Group Size: 512 KiB
HC WP Group Size: 8 MiB
User Capacity: 3.5 GiB ENH WRREL
User Enhanced Start: 0 Bytes
User Enhanced Size: 3.5 GiB
Boot Capacity: 4 MiB ENH
RPMB Capacity: 4 MiB ENH
=>
=> mmc dev
switch to partitions #0, OK
mmc0(part 0) is current device
=>
=> mmc erase 2 8

MMC erase: dev # 0, block # 2, count 8 ...

Caution! Your devices Erase group is 0x400
The erase range would be change to 0x0~0x3ff

8 blocks erased: OK


Thanks.
-Mike