Dell G15 Ryzen Edition (LA-K454P) – No SPI Activity, No Boot, No startup

[Raven7032]

Hello everyone!
Stucked with this problem.
Model: Dell G15 Ryzen Edition
Board: GDL LA-K454P
Symptoms:

• Board powers on (consumption ~0.5A), but no boot or display.
• Fans spin briefly, keyboard backlight turns on, then fans stop.
• Can be shut down via power button (EC active).
• No POST, no BIOS splash, no backlight.
• Led is blinking 2 orange 1 white
• No activity on SPI bus (no CS#, no CLK, no MOSI/MISO) even after pressing power.
• No APU_PCIE_RST# - 0V

Measurements:

• All voltage rails present: +1.8V, +0.75V, +3VS, +5VS, VDDCR_VDD, VDDCR_SOC, DDR VDDQ, VTT.
• EC_RSMRST# = 1.8V, SLP_S3#/S5# = 3.3V, APU_PWROK = 1.8V, APU_RST# = 1.8V
• DDR_A_RST# and APU_PCIE_RST# remain LOW (not deasserted).
• Checked SPI_CLK, CS#, MISO, MOSI on BIOS chip – no real activity.
• Reflashed BIOS with clean Dell BIOS Region (1.23.0) via external programmer.
• After CPU replacement nothing changed.

+3VS 3,4V
1.8VS 1,8V
0.75VS 0,75V
VDDCR_VDD 0,8V
VDDCR_SOC 0,8V
SYS_PWRGD_EC 3,3V
APU_RST# 2,1V
APU_PWROK 1,8V
C_RSMRST# 1.8V
13) SLP_S5# 3.3V
(14) SLP_S3# 3.3V
(15) SYSON 3.3V
(16) SUSP# 3.3V
(16) +1.2V_DDR 1.2V
(16) +1.2V_DDR
(17) +3VS 3.3V
(17) +3VS_APU 3.3V
(17) +1.8VS 1.8V
(19) +0.75VS 0.75V
(20) VGATE 3.4V
(20) +VDDCR_VDD 1V
(20) +VDDCR_SOC 1V
(21) SYS_PWRGD_EC 3.3V
(22) APU_PWROK 1.8V
(22) APU_RST# 1.8V

What I can check more? Seems CPU is not starting, but cant find reason why =(