15:03:51 <nikolam> tsoome, I have mailed you loader's ok prompt lsefi command , as requested. Here for the continuing of debugging it. 
15:04:47 <tsoome> I'd also like to see prtconf -vD | grep -w asy  
15:28:51 <tsoome> from lsefi, you should have 3 serial ports; PciRoot(0x0)/Pci(0x16,0x3)/Uart(115200,8,N,1) -- I think, its UART on PCI (to be confirmed from prtconf -vD), and PciRoot(0x0)/Pci(0x1F,0x0)/Acpi(PNP0303,0x0) and PciRoot(0x0)/Pci(0x1F,0x0)/Acpi(PNP0303,0x1) (ttya and ttyb on ISA, that is serial ports "onboard").
15:35:00 <tsoome> ah, silly me, PNP0303 should be ps/2 keyboard and mouse, not serial port...
15:36:30 <tsoome> so its down to one serial port;) 
15:44:16 <tsoome> Also, if you have chance to get on OK prompt: efi-show -g global,   But, I wonder if your loader is thinking it has ttya, but kernel is thinking it has term/0 -- check with ls /dev/term.  Only "onboard" ports are named ttya-ttyd
16:10:18 <nikolam> # prtconf -vD | grep -w asy  gives pci103c,8299, instance #0 (driver name: asy)
16:23:31 <tsoome> and ls /dev/term ?
16:27:33 <nikolam> tsoome,  ls /dev/term gives :  0   ;  ls -l /term  gives : 0 -> ../../devices/pci@0,0/pci103c,8299@16,3:0
16:28:22 <nikolam> let me send you another listing of efi-show -g global on mail
16:30:25 <nikolam> sent
16:30:54 <tsoome> yes, so it has no ttya, but term/0. You can try boot -B os_console=term/0  but Im not quite sure if it will do any good... early boot can not access it and kernel startup, Im not really sure if it will agree to attach console on term/0. 
16:31:17 <tsoome> its all built assuming ttya-ttyd.
16:40:26 <tsoome> no surprses from efi-show --ConIn and ConOut values are as expected.
16:40:34 <tsoome> surprises*
16:44:15 <nikolam> putting term/0 in loader boot does not change it. 
16:46:40 <tsoome> yea, was pretty sure it does not.
16:47:40 <nikolam> So there could be some settings in SmartOS to point to right terminal then
16:48:37 <nikolam> Also it is hard to even get Serial console runnin in Mesh Commander, I restart it few times and get it if Remote desktop/console is not active/connected .. 
16:58:09 <tsoome> basically thats the bad boy there: https://src.illumos.org/source/xref/illumos-gate/usr/src/uts/i86pc/io/consplat.c?r=82bb7c22#451
16:58:41 <tsoome> but its not all of it (as one might suspect). 
17:24:55 <nikolam> I plan to use serial console for Intel AMT or USB connected serial port plus some MCU as a cheapo replacement for full KVM, where not available for remote access. And Serial seems more useful because on SmartOS I am basically always in terminal, anyway. 
17:31:22 <nikolam> Maybe if I put something in my SmartOS post booting script that's started by service? So It activates serial console post boot