Dir-645 SEAMA linux.lzma ... LZMA ERROR

hello *,
just checked a new snapshot of openWRT-lede
and found, that the version from mon-/tuesday
09/10.04. is not able to flash.
The older version r6433-4fd8722056 mid of march
flashes flawlessly.

Maybe someone has a hint where to dig?

kernel changed from 4.9 to 4.14 ...

The serial console booting the new and todays build
and own one with imagebuilder

U-Boot 1.1.3 (Apr 15 2011 - 10:39:36) (ALPHA)
SVN revision: 516
Target board: WRG-N39

Board: Ralink APSoC DRAM:  64 MB
spi_wait_nsec: 30 
spi device id: 
find flash: MX25L6405D
raspi_read: from:30000 len:1000 
.raspi_read: from:30000 len:1000 
.============================================ 
Ralink UBoot Version: 3.3
-------------------------------------------- 
ASIC 3883_MP (MAC to REALTEK Mode)
DRAM component: 512 Mbits DDR, width 16
DRAM bus: 16 bit
Total memory: 64 MBytes
Flash component: SPI Flash
Date:Apr 15 2011  Time:10:39:36
============================================ 
icache: sets:512, ways:4, linesz:32 ,total:65536
dcache: sets:256, ways:4, linesz:32 ,total:32768 
gpio_init: write 0x00001801
gpio_init: write 0x0000185d to GPIOMODE(0xb0000060)

 Initializing RTL8367 GbE switch ...
 Setting RTL8367RB RGMII Delay time tx:1,rx0

Please choose the operation: 
   1: Load system code to SDRAM via TFTP. 
   2: Load system code then write to Flash via TFTP. 
   3: Boot system code via Flash (default).
   4: Entr boot command line interface.
   7: Load Boot Loader code then write to Flash via Serial. 
   9: Load Boot Loader code then write to Flash via TFTP. 
 0 
   
3: System Boot system code via Flash.
## Booting image at bc050000 ...
raspi_read: from:50000 len:40 
.raspi_read: from:50000 len:c 
.raspi_read: from:50000 len:359bbe 
......................................................We have SEAMA, Image Size = 3513214
Verifying Checksum ...
Uncompressing SEAMA linux.lzma ... LZMA ERROR 1 - must RESET board to recover

and the version r6433-4fd8722056.

U-Boot 1.1.3 (Apr 15 2011 - 10:39:36) (ALPHA)
SVN revision: 516
Target board: WRG-N39

Board: Ralink APSoC DRAM:  64 MB
spi_wait_nsec: 30 
spi device id:
find flash: MX25L6405D
raspi_read: from:30000 len:1000 
.raspi_read: from:30000 len:1000 
.============================================ 
Ralink UBoot Version: 3.3
-------------------------------------------- 
ASIC 3883_MP (MAC to REALTEK Mode)
DRAM component: 512 Mbits DDR, width 16
DRAM bus: 16 bit
Total memory: 64 MBytes
Flash component: SPI Flash
Date:Apr 15 2011  Time:10:39:36
============================================ 
icache: sets:512, ways:4, linesz:32 ,total:65536
dcache: sets:256, ways:4, linesz:32 ,total:32768 
gpio_init: write 0x00001801
gpio_init: write 0x0000185d to GPIOMODE(0xb0000060)

 Initializing RTL8367 GbE switch ...
 Setting RTL8367RB RGMII Delay time tx:1,rx0

Please choose the operation: 
   1: Load system code to SDRAM via TFTP. 
   2: Load system code then write to Flash via TFTP. 
   3: Boot system code via Flash (default).
   4: Entr boot command line interface.
   7: Load Boot Loader code then write to Flash via Serial. 
   9: Load Boot Loader code then write to Flash via TFTP. 
 0 
   
3: System Boot system code via Flash.
## Booting image at bc050000 ...
raspi_read: from:50000 len:40 
.raspi_read: from:50000 len:c 
.raspi_read: from:50000 len:33e05e 
....................................................We have SEAMA, Image Size = 3399710
Verifying Checksum ...
Uncompressing SEAMA linux.lzma ... OK
## Transferring control to Linux (at address 80000000) ...
## Giving linux memsize in MB, 64

Starting kernel ...

[    0.000000] Linux version 4.9.86 (buildbot@buildslave) (gcc version 7.3.0 (OpenWrt GCC 7.3.0 

Any help welcome.
thx