Should I give the hardware flash programmer a try, or is it useless without a full dump original image? By the way, when I tried to make a fpt -D out.bin it told me something is "locked", so only a partial dump was possible.

Well, I'm not exactly sure what you did followed and what not, so, if the system doesn't boot or always give the no output and no documented recovery option is available even after swapping or removing the memory or by forcing a substantial hardware change then you'll need to read the full content of the hardware chip and restore with a backup what's missing by hands.

@elektron
First thing first,I think you should find a full bios dumped by spi programmer and flashed it by SPI programmer later.

I will try to find a full spi BIOS dump (could be difficult), and get a spi programmer.

@noInk
The only thing I did (wrong) was to start the bios recovery in "yellow jumper open mode". I can't find a way to get a screen output or even a blue power LED since.
Thank you so much for your support to this point.

I would appreciate very much, if anyone could provide a spi BIOS dump from the SYSKLi35.86A

@elektron

Maybe the FD part survived and you just need to replace the ME segment with a factory new one but if the NUC doesn't boot now you need an hardware programmer capable to read it out and write it back.
By the image you posted it seems you used the recovery method with an update or something like that.
Supposedly, without the jumper and locked\broken ME you should have used the same ME bios version for the recovery first ( state change/reset ) and update it later from the shell or other normal boot path.
But it's intel software, so, who know what they where thinking.

@eivrah

Hey eivrah,
can you document in detail (PIN TO PIN, etc etc) how you got the DX58SO programmed without the SOW8 (Socketed SPI) and with the CH134A?
I've got an good condition DX58SO2 (Soldered SPI Flash) and it has the same DX58SO (501) issue at hardware programming with either the FLASHCAT and CH134A but I found the DediProg SF100 and it's SO8 CLIP is capable to reprogram in-circuit intel board.
( power on, forced power off 4 sec - power supply on system off )

@noInk I just clip using the diagram I sent, with or without peripherals it just works with my board. Us your CH134A the black model?

@eivrah

Yea, I'm using a Pomona SOIC-CLIP but same thing happen also with an hook type pin grabber.
If I connect the VCC on PIN8 the chip become undetected with the CH134A (CH134A ribbon cable soldered with the black CLIP = no detection ).

Can you spot any difference with your CH134A? Are you powering on the PSU? battery in/out?
are you sure it wasn't a fluke? can you check how high you can set the TRFC under the memory configuration page, should be 200 if the bios got written.

SIDE_A

@noInk have you tried changing the jumper wires to a shorter ones? My clip is just free from the CH134A that I bought, it's the same as yours. I didn't attached any power/pin. I'll check again later after I get home.

@eivrah

I'm using standard jump wire (dupont type) 20cm.
I'm in this situation where using all PIN in the assumed right position like in the CH341A ribbon cable cause the soldered in-circuit chip to become non-recognizable.
With the single head hook or the pin of the pomona clip I can test the following;

NO VCC on PIN8 >> right JEDEC ID chip detected equal FF content
3.3 VCC on PIN8 >> wrong JEDEC ID chip undetected NO content

This happen also with the FLASHCAT.
I did many other check on the pin-out and I m able to just read some partial data while in-circuit.

@gyrator

I just re-read your post and I'm experiencing the same issue with multiple intel board without the chip carrier for out-of-circuit programming.
I think the CH134A or other cheap hardware\software solution are not capable on handling the in-circuit bios chip operation whatsoever on these board.
The DX58SO2 I have naked here in front of me has all the required resistor and circuit to allow SPI flashing ( it's pretty much the same on the DQ77MK ).
Either some other signaling operation are required to allow the on-circuit flash or the hardware programmer provider didn't ever checked what going on with a logic analyzer / oscilloscope.

@noInk here's the pictures on this link Pics it's 200 max also I took a picture of my flasher.

@eivrah

Your CH134A is different, can you point me exactly where you got it? might be that?
Yep, if it's 200 then it got written by ISP.

It's from Shopee Ph page here it is CH341A Shopee Ph since I'm from Ph, but it ships from China around $5+. Why did you think it's different from yours? From the looks of it it's the same only the label at the back is different positioning?

@eivrah

That's would be hard for me but I probably found one with the same PCB as your.
I'll let you know when it arrive!
Yea, TEXT, resistor and some trace are different.