I'm in the same situation, I was able to hide all the boot messages after u-boot via settings in armbianEnv.txt.
Then I copied the SD to eMMC (faced this issue so I had to changed the boot script and regenerate) and updated the bootloader via nand-sata-install and now I have a verbose u-boot...
How should I apply the patch mentioned above ? Compile u-boot ? Any guidance on how to proceed ?
Thanks in advance for your help guys, much appreciated
OrangepiPC+ / 5.73 Jessie Legacy (yes, I know it's old but I need 'advanced' graphic control)