diff --git a/README.md b/README.md
index 367712a..321fd65 100644
--- a/README.md
+++ b/README.md
@@ -95,7 +95,7 @@ PCIe accelerators boards that you could use to accelerate your applications, Lit
 | ForestKitten33 | Xilinx Ultrascale+  | XCVU33P       | 125MHz   | PCIe | 2 x 1024-bit 4GB HBM2*|  Gen3 X16     |     ?       |
 | BCU1525        | Xilinx Ultrascale+  | XCVU9P        | 125MHz   | PCIe | 4 x 64-bit DDR4 DIMM  |  Gen3 X16     |     ?       |
 | AlveoU250      | Xilinx Ultrascale+  | XCU250        | 125MHz   | PCIe | 4 x 64-bit DDR4 DIMM  |  Gen2 X16     |     ?       |
-| AlveoU280      | Xilinx Ultrascale+  | XCU280        | 125MHz   | PCIe* | 2 x 64-bit DDR4 DIMM* & HBM2*  |  Gen2 X16     |     ?       |
+| AlveoU280      | Xilinx Ultrascale+  | XCU280-ES1    | 150MHz   | PCIe* | 2 x 64-bit DDR4 DIMM <BR> 2 x 1024-bit 4GB HBM2* |  Gen2 X16     |     ?       |
 
 \* Present on the board but not yet supported or validated with LiteX.
 
diff --git a/litex_boards/targets/xilinx_alveo_u280.py b/litex_boards/targets/xilinx_alveo_u280.py
index 11ffee3..3f31d55 100755
--- a/litex_boards/targets/xilinx_alveo_u280.py
+++ b/litex_boards/targets/xilinx_alveo_u280.py
@@ -57,12 +57,12 @@ class _CRG(Module):
 # BaseSoC ------------------------------------------------------------------------------------------
 
 class BaseSoC(SoCCore):
-    def __init__(self, sys_clk_freq=int(150e6), ddram_channel=0, with_pcie=False, **kwargs):
+    def __init__(self, sys_clk_freq=int(150e6), ddram_channel=0, with_pcie=False, with_led=False, **kwargs):
         platform = alveo_u280.Platform()
 
         # SoCCore ----------------------------------------------------------------------------------
         SoCCore.__init__(self, platform, sys_clk_freq,
-            ident          = "LiteX SoC on Alveo U280",
+            ident          = "LiteX SoC on Alveo U280 (ES1)",
             ident_version  = True,
             **kwargs)
 
@@ -73,8 +73,9 @@ class BaseSoC(SoCCore):
         if not self.integrated_main_ram_size:
             self.submodules.ddrphy = usddrphy.USPDDRPHY(platform.request("ddram", ddram_channel),
                 memtype          = "DDR4",
+                cmd_latency      = 1, # seems to work better with cmd_latency=1
                 sys_clk_freq     = sys_clk_freq,
-                iodelay_clk_freq = 500e6,
+                iodelay_clk_freq = 600e6,
                 is_rdimm         = True)
             self.add_sdram("sdram",
                 phy           = self.ddrphy,
@@ -94,9 +95,10 @@ class BaseSoC(SoCCore):
             self.add_pcie(phy=self.pcie_phy, ndmas=1)
 
         # Leds -------------------------------------------------------------------------------------
-        self.submodules.leds = LedChaser(
-            pads         = platform.request_all("gpio_led"),
-            sys_clk_freq = sys_clk_freq)
+        if with_led:
+            self.submodules.leds = LedChaser(
+                pads         = platform.request_all("gpio_led"),
+                sys_clk_freq = sys_clk_freq)
 
 # Build --------------------------------------------------------------------------------------------
 
@@ -108,6 +110,7 @@ def main():
     parser.add_argument("--ddram-channel",default="0",         help="DDRAM channel (default: 0)")
     parser.add_argument("--with-pcie",    action="store_true", help="Enable PCIe support")
     parser.add_argument("--driver",       action="store_true", help="Generate PCIe driver")
+    parser.add_argument("--with-led",     action="store_true", help="Enable LED Chaser")
     builder_args(parser)
     soc_core_args(parser)
     args = parser.parse_args()
@@ -116,6 +119,7 @@ def main():
         sys_clk_freq = int(float(args.sys_clk_freq)),
         ddram_channel = int(args.ddram_channel, 0),
         with_pcie    = args.with_pcie,
+        with_led    = args.with_led,
         **soc_core_argdict(args)
 	)
     builder = Builder(soc, **builder_argdict(args))