docs: PROTOCOL.md: specify TCR_EL1/TTBR0_EL1 values for base revision > 0
diff --git a/PROTOCOL.md b/PROTOCOL.md
index e497ad62..92515fb9 100644
--- a/PROTOCOL.md
+++ b/PROTOCOL.md
@@ -321,7 +321,10 @@ instructions or registers.
Higher ELs do not interfere with accesses to the generic timer and counter.
-The used translation granule size is undefined.
+The used translation granule size for both `TTBR0_EL1` and `TTBR1_EL1` is 4KiB.
+
+For base revisions > 0, `TCR_EL1.T0SZ` is set to 16, and `TTBR0_EL1`
+is left undefined.
If booted by EFI/UEFI, boot services are exited.
