[docs] Update README.md

* Document --gbl-path and --clean-cipd options for fuchsia_build.py.

Bug: 404925473
TAG=agy
CONV=808a55a0-4d86-4dff-8034-492f4ea0d365

Change-Id: I6647c49d75150d5ef6e361e0045e2e2c1478c29c
Reviewed-on: https://turquoise-internal-review.googlesource.com/c/third_party/u-boot/+/1379311
Reviewed-by: David Pursell <dpursell@google.com>
Commit-Queue: Sergii Parubochyi <sergiip@google.com>
GitOrigin-RevId: 5f51a97c4fbfeed365bd4e2e35165e4f9a0e0eef

README.md

diff --git a/README.md b/README.md
index e74a348..4588de3 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,3 @@
-# SPDX-License-Identifier:	GPL-2.0+
-# u-boot
-
 This is a version of u-boot, modified to support Fuchsia on the Khadas vim3
 
 Building vim3 Bootloader for Fuchsia
@@ -14,12 +11,17 @@
 ```
 ./fuchsia_build.py
 ```
-`--clean-cipd` option can be used to make sure CIPD checkout is clean. It will
-remove `cipd_deps` directory and download dependencies again.
+Options:
+* `--clean-cipd` option can be used to make sure CIPD checkout is clean. It will
+  remove `cipd_deps` directory and download dependencies again.
+* `--gbl-path <path>` option specifies a path to a local GBL (`gbl.efi`)
+  binary. If provided, CIPD GBL is not used; otherwise, the script downloads
+  GBL from CIPD and uses `gbl_aarch64_dev.efi`.
 
 You now have a `build/u-boot.bin.unsigned` that you can flash to a target
 using fastboot.
 
-`fuchsia_upload.py` is used to upload commits to open repository.
-And upload binaries to CIPD.
+Releasing and Uploading
+=======================
 
+go/fuchsia-firmware-licensing-publishing