[U-Boot] u-boot - raspberry pi

[dh at synoia.com]

 We have u-boot working on a raspberry pi, but need to append our kernel
 parms to those built by the firmware.

is there a version of u-boot for the pi 3, with this support, and some doc
(the variable name for the firmware built kernel parms), a github link would
be perfect.

We have an order of 400 PIs for a hospital in S America, and want to supply
net boot, including kernels. Duncan Hare

714 931 7952