SamyGO

Message:
Hello everyone,

I'm hoping to get some advice from the experts here, as I've hit a wall with my current repair project.

Model: Samsung UN65F8000 (F-Series, Fox.P Chassis)
Mainboard: BN94-07163A / BN97-07574F

The Symptom:
My TV is stuck in an endless bootloop. The backlight turns on, the Smart TV logo appears, and the TV stays on for about 60 seconds. After exactly these 60 seconds, it crashes and the reboot cycle starts all over again.

My Diagnosis & UART Log:
I connected to the UART port and the log shows that it fails during the authentication process, most likely due to a corrupted partition (bad blocks) on the eMMC. Here is the exact end of the log right before it shuts down:

[CIP_AUTHULD] Errnum 1007
[CIP_AUTHULD] error part. number = 2
[CIP_AUTHULD] System will be down.(0x2)
[CIP_KERNEL] authentication fail!!
[CIP_KERNEL] [init/main.c::Exception_from_authuld::848]auth failed in kernel. System Down.

Troubleshooting already done:
I tried to access the U-Boot console to hopefully fix or format the partition. I shorted the Main EEPROM SDA (M_E_SDA) to GND during power-on. The boot process slowed down significantly (throwing hundreds of i2c 0 port recovery is failed errors in PuTTY), but unfortunately, I could NOT interrupt the boot sequence by spamming ESC or Enter. It seems bootdelay=0 is set in this firmware version.

My Question to the community:
Is there any other known testpoint or trick to force this specific board into the U-Boot prompt? Or is the only way left to replace/reprogram the eMMC via ISP/BGA rework?

Thank you so much in advance for your time and any help you can provide!

Best regards,
X-Rocky

Something similar happens to my ES8000 even if I did not have the time to investigate by UART etc...
I managed to get out of this situation with a factory reset .... but also this was a temporary solution as sometimes the boot loop restart.

I found that unplug from the wall during boot loop has a benfic effect on this issue but in my case I believe there are two possibilities:
1) TV was rooted and some log have increased so much that there is not anymore the space for nominal behaviour. I have unrooted but the issue remains (the samygo injection is quite invasive.
2) TV Power Supply is going to die...

In your case I see that it is repetitive every 60 seconds, the situation seems different.
Was you TV rooted ?
Did you force the start from partition 1 by manual mod of configuration system files ? if this is the case you cannot do anything to fix it as it was to be signed berore to reboot ; as far as I remember there is not a fix in this situation other than reflash the memories on the main board with an external programmer.