There is no fastboot mode after install new aosp bootloader

I installed aosp bootloader version 6123 by following " Flashing the device" section in documentation. after flashing I see this output in the serial connection.

UEFI Start     [ 2480] SEC
ASLR        : On
DEP         : On
Timer Delta : +1 mS
RAM Entry 0 : Base 0x0000000080000000  Size 0x00000000FDFA0000
UEFI Ver    : 5.0.190528.BOOT.XF.2.0-00371-SDM845LZB-1
Build Info  : 64b May 28 2019 11:21:44
Boot Device : UFS
PROD Mode   : TRUE
Retail      : TRUE
PM0: 20, PM1: 21, PM2: 24, 
MDDPlatform DDC No Ack or Abitration lost
not panel detected, use defualt panel !
DisplayDxe: Resolution 1920x1080 (1 intf)
Render Splash  [ 3199]
-----------------------------
Platform Init  [ 3254] BDS
Platform   : MTP
Chip Name  : SDA845
Chip Ver   : 2.1
Core 0 Freq: 1612 MHz
-----------------------------
UEFI Total : 2447 ms
POST Time      [ 4927] OS Loader

LaunchAppFromGuidedFv: Could not find required guided FV
Press any key to shutdown

the board can not enter fastboot mode now. how can I install android image ?

thanks.

@274_4194 Hi I am facing same issue which you mentioned above, did you find any resolution?

Hello @Liquancin , I tried version 107 and it worked.