diff --git a/JOURNAL.md b/JOURNAL.md
index d103ff3..84245af 100644
--- a/JOURNAL.md
+++ b/JOURNAL.md
@@ -1176,3 +1176,33 @@ request Ctrl+O then 'z'.
 
 Maybe I can try disabling the huge pages, just to discard that it may be
 related to it: `CONFIG_HUGETLBFS`.
+
+Same hang with huge pages disabled, but a bit further ~70 MB.
+
+### OBSERVATION: The Linux memtest fails in the first round
+
+    [    0.000000] Linux version 6.9.7 (nixbld@localhost) (riscv64-unknown-linux-gnu-gcc (GCC) 13.3.0, GNU ld (GNU Binutils) 2.41) #1-NixOS Thu Jun 27 11:52:32 UTC 2024
+    [    0.000000] Machine model: Barcelona Supercomputing Center - Lagarto Ox (NixOS)
+    [    0.000000] SBI specification v2.0 detected
+    [    0.000000] SBI implementation ID=0x1 Version=0x10004
+    [    0.000000] SBI TIME extension detected
+    [    0.000000] SBI IPI extension detected
+    [    0.000000] SBI RFENCE extension detected
+    [    0.000000] SBI DBCN extension detected
+    [    0.000000] earlycon: sbi0 at I/O port 0x0 (options '')
+    [    0.000000] printk: legacy bootconsole [sbi0] enabled
+    [    0.000000] Reserved memory: created DMA memory pool at 0x0000000060000000, size 256 MiB
+    [    0.000000] OF: reserved mem: initialized node dma_pool@60000000, compatible id shared-dma-pool
+    [    0.000000] OF: reserved mem: 0x0000000060000000..0x000000006fffffff (262144 KiB) map non-reusable dma_pool@60000000
+    [    0.000000] Reserved memory: created DMA memory pool at 0x0000000070000000, size 256 MiB
+    [    0.000000] OF: reserved mem: initialized node dma_pool@70000000, compatible id shared-dma-pool
+    [    0.000000] OF: reserved mem: 0x0000000070000000..0x000000007fffffff (262144 KiB) map non-reusable dma_pool@70000000
+    [    0.000000] cma: Reserved 16 MiB at 0x00000000bf000000 on node -1
+    [    0.000000] early_memtest: # of tests: 3
+    [    0.000000]   0x0000000080000000 - 0x0000000080013000 pattern 5555555555555555
+
+This is not suggesting that the problem is not in the virtual memory, but with
+the actual physical memory.
+
+I will try a similar test with uboot with the `mtest` command, but requires
+enabling it first.
diff --git a/lagarto-ox.nix b/lagarto-ox.nix
index 292986d..f9208ca 100644
--- a/lagarto-ox.nix
+++ b/lagarto-ox.nix
@@ -253,6 +253,7 @@
         CONFIG_DEBUG_SBI_CONSOLE=y
         CONFIG_SMP=n
         CONFIG_TRACE_EARLY=y
+        CONFIG_CMD_MEMTEST=y
       ''
 #      # Enable debug logs
 #      +