Hi !
I contacted the user, he can confirm that those two laptops *never* started from USB sticks made with Tails Installer.
so, here is my patch. It's also adding Aegis secure key 3.0 to the problematic usb sticks. 
I hope that all will be ok this time...
cheers.
From 9947b1039fac6ae113ffadddc214be57c7e45864 Mon Sep 17 00:00:00 2001
From: Debian Live user <amnesia@???>
Date: Fri, 10 Apr 2015 17:13:16 +0000
Subject: [PATCH 1/2] add Aegis USB3 secure keys to the problematic usb stick
---
 wiki/src/support/known_issues.mdwn |    6 ++++++
 1 file changed, 6 insertions(+)
diff --git a/wiki/src/support/known_issues.mdwn b/wiki/src/support/known_issues.mdwn
index 3ce66e6..ff82601 100644
--- a/wiki/src/support/known_issues.mdwn
+++ b/wiki/src/support/known_issues.mdwn
@@ -54,8 +54,14 @@ and are prone to failure.
 
 ### Aegis
 
+* Aegis Secure Key USB 2.0
+
 During the boot process, USB is briefly powered off, that causes Aegis hardware-encrypted USB sticks to lock down, and the PIN must be entered again (fast) in order to complete the boot.
 
+* Aegis Secure Key USB 3.0
+
+This USB stick doesn't start Tails at all, the USB 2.0 workaround is not working for that hardware.
+
 ### Other vendors
 
 * Staples Relay USB 2.0 16GB, suffers from the same problem as [[some SanDisk USB sticks|known_issues#sandisk]].
-- 
1.7.10.4
From a000a106ea95a94c6f3a0d63651bd497e7a7e1ad Mon Sep 17 00:00:00 2001
From: Debian Live user <amnesia@???>
Date: Fri, 10 Apr 2015 17:15:40 +0000
Subject: [PATCH 2/2] add two laptops to the known issues list
---
 wiki/src/support/known_issues.mdwn |   10 ++++++++++
 1 file changed, 10 insertions(+)
diff --git a/wiki/src/support/known_issues.mdwn b/wiki/src/support/known_issues.mdwn
index ff82601..f5b4266 100644
--- a/wiki/src/support/known_issues.mdwn
+++ b/wiki/src/support/known_issues.mdwn
@@ -75,6 +75,11 @@ using Tails Installer.
 This problem might be corrected in Tails 1.1 and newer: please report
 your test results back to us.
 
+Acer Aspire 5315-ICL50
+----------------------
+
+Does not start on USB sticks created using Tails Installer.
+
 ASUS VivoBook X202E
 -------------------
 
@@ -134,6 +139,11 @@ Cannot start neither from USB nor from DVD. System crashes with a blank
 screen and locked up keyboard. This problem might be corrected in
 newer versions: please report your test results back to us.
 
+Fujitsu Siemens Amilo A 1667G
+-----------------------------
+
+Does not start on USB sticks created using Tails Installer.
+
 HP Compaq dc5750 Microtower
 ---------------------------
 
-- 
1.7.10.4