Technexion PICO-PI-IMX6ULL hangs after SPL

[hmojito]

I'm trying to flash a custom yocto image to a Technexion PICO-IMX6UL to emmc using uuu from their git:

sudo ~/imx-mfgtools-tn/uuu/uuu -v -b emmc_imx6ul_img SPL-pico-imx6ul u-boot.img imx-image-full-pico-imx6ul.wic.bz2/*
uuu (Universal Update Utility) for nxp imx chips -- libtn-uuu_1.4.77_20210421-0-g82a545a

Build in config:
	Pctl	 Chip		 Vid	 Pid	 BcdVersion
	==================================================
	SDPS:	 MX8QXP		 0x1fc9	 0x012f	 [0x0002..0xffff]
	SDPS:	 MX8QM		 0x1fc9	 0x0129	 [0x0002..0xffff]
	SDPS:	 MX8DXL		 0x1fc9	 0x0147
	SDPS:	 MX28		 0x15a2	 0x004f
	SDPS:	 MX815		 0x1fc9	 0x013e
	SDPS:	 MX865		 0x1fc9	 0x0146
	SDPS:	 MX8ULP		 0x1fc9	 0x014a
	SDPS:	 MX8ULP		 0x1fc9	 0x014b
	SDP:	 MX7D		 0x15a2	 0x0076
	SDP:	 MX6Q		 0x15a2	 0x0054
	SDP:	 MX6D		 0x15a2	 0x0061
	SDP:	 MX6SL		 0x15a2	 0x0063
	SDP:	 MX6SX		 0x15a2	 0x0071
	SDP:	 MX6UL		 0x15a2	 0x007d
	SDP:	 MX6ULL		 0x15a2	 0x0080
	SDP:	 MX6SLL		 0x1fc9	 0x0128
	SDP:	 MX7ULP		 0x1fc9	 0x0126
	SDP:	 MXRT106X	 0x1fc9	 0x0135
	SDP:	 MX8MM		 0x1fc9	 0x0134
	SDP:	 MX8MQ		 0x1fc9	 0x012b
	SDPU:	 SPL		 0x0525	 0xb4a4	 [0x0000..0x04ff]
	SDPV:	 SPL1		 0x0525	 0xb4a4	 [0x0500..0x9998]
	SDPU:	 SPL		 0x0525	 0xb4a4	 [0x9999..0x9999]
	SDPU:	 SPL		 0x3016	 0x1001	 [0x0000..0x04ff]
	SDPV:	 SPL1		 0x3016	 0x1001	 [0x0500..0x9998]
	FBK:	 		 0x066f	 0x9afe
	FBK:	 		 0x066f	 0x9bff
	FB:	 		 0x0525	 0xa4a5
	FB:	 		 0x18d1	 0x0d02
	FB:	 		 0x3016	 0x0001

Run built-in script:
 
uuu_version 1.2.39

# @SPL-pico-imx6ul                 | secondary program loader, ex: SPL
# @u-boot.img               | mainly loader which loaded to DDR, ex: u-boot.img
# <li-user uid="40832" login="imx"></li-user>-image-full-pico-imx6ul.wic.bz2/*       | whole system image which generated by Yocto.

# This command will be run when i.MX6/7
SDP: boot -f SPL-pico-imx6ul

# These commands will be run when use SPL and will be skipped if no spl
# if (SPL support SDPV)
# {
SDPV: delay 1000
SDPV: write -f  u-boot.img -addr 0x877FFFC0
SDPV: jump -addr 0x87800000
# }


FB: ucmd setenv fastboot_dev mmc
FB: ucmd setenv mmcdev ${mmc_dev}
FB: ucmd mmc dev ${mmc_dev}
FB: flash -raw2sparse all imx-image-full-pico-imx6ul.wic.bz2/*
FB: ucmd if env exists emmc_ack; then ; else setenv emmc_ack 0; fi;
FB: ucmd mmc partconf dev ${mmc_dev} ${emmc_ack} 0 0
FB: done


Wait for Known USB Device Appear...
New USB Device Attached at 1:2
1:2>Start Cmd:SDP: boot -f SPL-pico-imx6ul
6400%1:2>Okay (0.921s)

From serial console :

U-Boot SPL 2021.04-e541d8646828d44a8b29e4cbac47e6d7cf729613+ge541d86468 (Jun 23 2022 - 06:59:51 +0000)
Trying to boot from USB SDP
SDP: initialize...
SDP: handle requests...

But after this nothing happens... I'm little bit confused about what I need to change/test/or modify to complete flash sequence, is someone already faced to the same issue?