Need: a NEEDLE, SD-card 256M-8GB. To control the firmware process, a USB-TTL-COM-port adapter is desirable. J1 1-Gnd, 4-Rx, 5-Tx.

If the L3+ board does not fully start, all 4 blue LEDs do not light up (of course, if the internal nand flash is not dead at all).
If the board does not boot or sew with a factory restore L3 + SD-card from Bitmain. Read instruction after purchase.
In case of failure, no claims will be accepted, go for it at your own peril and risk.