Unfortunately that says APPEND {cbootargs} rootfstype=ext4 root=/dev/mmcblk0p1 rw rootwait which means that "quiet" comes from {cbootargs}
How can I change ${cbootargs} ?
The command line in effect is:
tegraid=21.1.2.0.0 ddr_die=4096M@2048M section=512M memtype=0 vpr_resize usb_port_owner_info=0 lane_owner_info=0 emc_max_dvfs=0 touch_id=0@63 video=tegrafb no_console_suspend=1 console=ttyS0,115200n8 debug_uartport=lsport,0 earlyprintk=uart8250-32bit,0x70006000 maxcpus=4 usbcore.old_scheme_first=1 lp0_vec=0x1000@0xff780000 core_edp_mv=1075 core_edp_ma=4000 tegra_fbmem=0x800000@0x92cb6000 is_hdmi_initialised=1 root=/dev/mmcblk0p1 rw rootwait console=ttyS0,115200n8 console=tty0 fbcon=map:0 net.ifnames=0 root=/dev/mmcblk0p1 rw rootwait console=ttyS0,115200n8 console=tty0 fbcon=map:0 net.ifnames=0 rootfstype=ext4 root=/dev/mmcblk0p1 rw rootwait
So, this means that I could copy-and-paste all of those additional parameters, with the changes I want, and exclude ${cbootargs} entirely. It’d be better if there was some way to get into that chain at an earlier point.
It’s also interesting that ${cbootargs} includes “root=/dev/mmcblk0p1 rw rootwait” which "makes the extlinux.conf redundant. The “console=ttyS0,115200n8” is specified three times, and “console=tty0 fbcon=map:0 net.ifnames=0” is specified at least twice.
Seems like this entire path could be cleaned up a little bit …
Interestingly, there is no “quiet” in the boot line, so the original request is probably looking for the wrong thing.