Dear all,
my plan is to use the a BeagleBoard-X15 as an homeserver for different tasks within a home automation. Therefore it should work as a secure gatway between to networks (normal Network for Laptop/Android phone on the one hand and all parts that belong to home automation on the other). All tasks can be handled by the board but at one point I am stuck. In case of a power loss the x15 won’t boot without me pressing the button to reboot it. This is not practical for me as I want to able to access the system behind the gateway remotely (especially after any kind of powerloss to see if everything is ok 
). Is there anyway to solve this kind of problem? I read that wake on lan is not provided by the board. Is it possible to “implement a power on after power fail”? I have a second BeagleBoneBlack, would there be a way of using its GPOI Pins to start the X15?
I am open to any kind of solution.
Thanks in advance
Tschibi
On Page 3:
https://github.com/beagleboard/beagleboard-x15/blob/master/BEAGLEBOARD_X15_REV_B1.pdf
The keyword is "JTAG" and make sure you "always" have a working
"U-Boot" installed to microSD/eMMC. 
Regards,
Hi Robert,
thank you for your help. If I do understand right, I have to insert a wire in LDO_VRTC to enable JTAG. As long as there is a working Uboot the X15 will power on after power loss. Please correct me if I am wrong. I don’t have that much experience with JTAG.
Best Regards
Tschibi
We placed a wire across the J5 jumper (ties PMIC POWERHOLD to LDO_VRTC) to permit the BB-X15 to boot up after power loss without having to press the power button. Normally without the jumper, the PMIC (power management chip) shuts the am5728 down within a fixed time window after powerup. Placing a wire across the J5 jumper allows the PMIC to keep the Sitara 5728 powered on all the time, thus not requiring the user to press the power or RESET buttons to boot the BB-X15. Normal mode of operation after pressing the power button with a valid u-boot present is for u-boot to send a message to the PMIC to remain powered on. But with the jumper populated, this isn’t needed to allow the PMIC to keep the 5728 powered.
For our custom board, based on the BB-X15 design, we populated the J5 jumper to permit re-booting of Linux through power cycles of the board. This technique works for us. TI provides additional information on this, if you care to wade through all of the jargon, https://e2e.ti.com/support/applications/automotive/w/design_notes/3266.should-i-use-powerhold-or-pwron-to-turn-on-the-pmic
Incidentally, if you do connect JTAG with CCS, TI provides a set of GEL (target initialization) files which send the “stay powered” message to the PMIC. I believe the GEL files run when the user attempts to connect to the A15 core(s) via CCS. But you have to quickly connect to the A15 core(s) after pressing the power button before the PMIC shuts everything down again.
As far as I know there is a pin on the expansion board that runs parallel to the start button (Port 18 ), so its matter to use either a 555 or and electronic arrangement with a diode that pulls down the pin (Beagleboard starts with a falling edge) to start it whenever it detects power. The J5 pins are a good option but in the TI forums they are quite vocal about not using that option since it can damage permanently the board (I don’t understand why, my best guess is that if the beagleboard doesn’t start right away the fan wont start so it will burn).
That's why you "must" always have a known good version of u-boot spl in
microSD or eMMC... If you use J5...
Regards,