DE10-Lite Memory initialization failed

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DE10-Lite board litex boot with sdram enabled fails on memory read/write test
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BIOS built on Sep 5 2023 00:01:20
BIOS CRC passed (c7231e8a)

LiteX git sha1: 88532150

--=============== SoC ==================--
CPU: VexRiscv @ 50MHz
BUS: WISHBONE 32-bit @ 4GiB
CSR: 32-bit data
ROM: 128.0KiB
SRAM: 8.0KiB
L2: 8.0KiB
SDRAM: 64.0MiB 16-bit @ 50MT/s (CL-2 CWL-2)
MAIN-RAM: 64.0MiB

--========== Initialization ============--
Initializing SDRAM @0x40000000...
Switching SDRAM to software control.
Switching SDRAM to hardware control.
Memtest at 0x40000000 (2.0MiB)...
Write: 0x40000000-0x40200000 2.0MiB
Read: 0x40000000-0x40200000 2.0MiB
bus errors: 256/256
addr errors: 0/8192
data errors: 524288/524288
Memtest KO
Memory initialization failed`

I see it is using GENSDRPHY(https://github.com/litex-hub/litex-boards/blob/master/litex_boards/targets/terasic_de10lite.py). FYI, DE10 Lite board was removed from linux-on-litex-vexriscv due to this issue (see litex-hub/linux-on-litex-vexriscv#154)

BTW, I tried with both DM pins to active low (thought would work since there are boards with DM pins grounded ) but no luck. I am not good at memory controller but I can help on testing the fix.