Upgrading uboot on Creta

[glinoob]

There may be pointers to relevant info here:

Cannot uboot a new firmware to AR750S-EXT

hello, thanks, when trying to uboot a new firmware, openwrt-ar750s-3.212-0407.img. each time i try, i get the following error UPDATE FAILED Something went wrong during update Probably you have chosen wrong file (too big or too small) or you were trying to update ART on device with unknown FLASH type (and size) which is not allowed. Please, try again or contact with the author of this modification. You can also get more information during update in U-Boot console. so far i have tried. — made…

Edit: maybe also here:

AR-750S Uboot recovery not working

Trying to upload a custom firmware build to an AR-750s and for some reason just cannot convince U-boot to talk to me! Hooked up the UART (maybe in the future those pins could come populated instead of just open guys… since the heatsink practically blocks the bottom of them and makes soldering especially fun), and I can see that UBoot properly goes into HTTP recovery mode if I hold the reset button for 5+ LED flashes. An yet, no connectivity. I have tried two different laptops, each of the three…