@Pasi, thanks a lot for the pointer. It solved it for me.
I first checked if I was able to flash Jetpack 3.2 on dev kit and it went through with HDMI working.
The JetPack flash command is
./tegraflash.py
--bl nvtboot_recovery_cpu.bin
--sdram_config P3310_A00_8GB_Samsung_8GB_lpddr4_204Mhz_A02_l4t.cfg
--odmdata 0x1090000
--applet mb1_recovery_prod.bin
--cmd "flash; reboot"
--cfg flash.xml
--chip 0x18
--misc_config tegra186-mb1-bct-misc-si-l4t.cfg
--pinmux_config tegra186-mb1-bct-pinmux-quill-p3310-1000-c03.cfg
--pmic_config tegra186-mb1-bct-pmic-quill-p3310-1000-c04.cfg
--pmc_config tegra186-mb1-bct-pad-quill-p3310-1000-c03.cfg
--prod_config tegra186-mb1-bct-prod-quill-p3310-1000-c03.cfg
--scr_config minimal_scr.cfg
--scr_cold_boot_config mobile_scr.cfg
--br_cmd_config tegra186-mb1-bct-bootrom-quill-p3310-1000-c03.cfg
--dev_params emmc.cfg
--bins "mb2_bootloader nvtboot_recovery.bin; mts_preboot preboot_d15_prod_cr.bin; mts_bootpack mce_mts_d15_prod_cr.bin; bpmp_fw bpmp.bin; bpmp_fw_dtb tegra186-a02-bpmp-quill-p3310-1000-c04-00-te770d-ucm2.dtb; tlk tos.img; eks eks.img; bootloader_dtb tegra186-quill-p3310-1000-c03-00-base.dtb"
After verifications in tegra186-flash-helper.sh the command is identical to B0[1-9] version.
Then I flashed my image on Astro and everything works.
I’ll submit the fix to meta-tegra layer.
Cheers!