by summers » Mon Aug 31, 2020 1:47 pm
Sigh
$this->bbcode_second_pass_quote('', 'S')o, you can't provide answer (YES/NO) to the question:
"Is it possible to run just 3 phases of the bootloader, then stop at the bootloader prompt (i.e. stop at U-Boot # ... without kernel loading) ?
1) attach a 3.3V UART to serial connector to the UART pins on the BBB
2) attach the serial connector to another computer
3) set a terminal on that computer to connect to the serial port
4) switch on the BBB
5) immediately on the other computer hit space bar
6) uboot on the BBB is interrupted, and drops to the uboot prompt
7) type commands to you hearts content
So yes on *all* version of uboot, its possible to interrupt it.
This is what was written above, in less detail. If you need all this detail, its clear you don't understand how these arm embedded board work, and how uboot has been so good. uboot brings up minimal of what it can, e.g. the memory controllers, and the cpu, and a uart. This is why communication to the uart is important.